[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi all,

Thanks for dialing in to the meeting this week.

Going forward, in order to conserve everyone's time, we will be polling ahead
of time for an agenda, and foregoing the online meeting in favor of voluntary
email updates if no agenda is suggested. I will send out a reminder for an
agenda the day before this scheduled meeting if one hasn't been suggested.

Cheers,
Brenden

=== Discussion ===

This meeting has become somewhat repetitive, and often lacks an agenda.
The discussion that focuses around status isn't too useful.
The goal of the meeting should be to discuss specific issues.
  Please send issues to discuss prior to the meeting, otherwise send regular
  updates (if useful) in email format.

Brendan:
Book is not visible online yet, waiting on publisher
Reviewers are still looking at pre-copy-edit versions

Question for kernel devs: how does the verifier handle divide by zero?
Should the book call the BPF a VM or runtime? Answer: runtime
  It is also an instruction set.
  Any mention of turing completeness?
... waiting for bpf runtime written in bpf :)


=== Attendees ===
Brenden Blanco
Michael Savisko
Bjorn Topel
Jesper Brouer
Jakub Kicinski
Daniel Borkmann
Jiong Wang
Alexei Starovoitov
Joe Stringer
Marco Leogrande
Martin Lau
Maciej Fijalkowski
Brendan Gregg
Dan Siemon
John F
Quentin Monnet
Richard Elling

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi all,

Thanks for joining in to the call today. As usual, here are my notes.

Cheers,
Brenden

=== Discussion ===

Daniel:
- Some cilium debugging for loadbalancing case
- Fix sendmsg hooks for unconnected udp
  - should fix dns resolution issue in cilium

Yonghong:
- Released new bcc version (0.10.0)
- Some new revisions in LLVM for CO-RE support
- bpf_send_signal is complete, support being added to libbpf

Brendan:
- nearing book deadline, send in your last minute reviews

Alexei:
- CFP for Linux Plumbers is open (Sep 9-11, Portugal)
  - https://www.linuxplumbersconf.org/event/4/abstracts/
- BPF subtrack will be taking place (some overlap with networking)

Maciej:
- working XSK (AF_XDP socket) support in libbpf
  - some issues without an obvious solution, details to be sent to mailing list

=== Attendees ===
Brenden Blanco
Florian Lehner
Paul Chaignon
Dan Siemon
Richard Elling
Andy Gospodarek
Marco Leogrande
Maciej Fijalkowski
Daniel Borkmann
Alexei Starovoitov
Jiong Wang
Jakub Kicinski
Jesper Brouer
Brendan Gregg
Mauricio Vasquez
Joe Stringer

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[iovisor-dev] minutes: IO Visor/TSC Dev Meeting

[Brenden Blanco]

Hi all,

Thanks for joining the call today. As usual, here are my notes from the
discussion.

=== Discussion ===
Alexei:
LSF/MM - BPF track
* overall went quite well
* planning BPF conference for next year
* notes @ http://vger.kernel.org/bpfconf2019.html

Yonghong:
* Compiler work to support compile-once-run-anywhere
  * LLVM code review fabricator - search for yonghong to find patch
* Send signal bpf helper RFC1 has some issues
  * trying instead to send to current, even if in interrupt context
* Other updates: some work for map of maps support in bcc

John:
* Some progress on bounded loop
  * Performing arithmetic on induction variables in one pass through loop
  * Many loops have simple enough induction variable strides to satisfy this
simple algorithm
* other sockmap and ktls fixes
  * release/acquire socket lock issue in ktls
  * fuzzing fixes

Jiong:
* 32 bit patchset work continues
  * Currently determining how to test
  * Setting up arm 32 bit qemu environment has issues
* Cross-compiling kernel + selftest suite
  * Some offers to test on 32 bit x86

Brendan:
* BPF book is currently being reviewed
  * If someone on the call would like to contribute reviews, reach out to
Brendan
  * bpftrace syntax to be finalized
  * some compiler hints would be nice to pass __user pointer annotation to the
scripts, otherwise explicit wrapper is necessary
  * necessary only for mixed mode tools

Joe:
* socket_assign helper for proxying support in bpf
  * tproxy working for tcp, working on udp
  * skc_lookup[_tcp] helper needed?
  * some leakiness in the socket api/bpf abstraction, needs to be worked out

Daniel:
* Out of bounds fix
* cgroups hooks for sendmsg
  * breaks for DNS
  * add recvmsg hooks for reverse path, to avoid lookup failure
  * some minor fixes for connected (tcp) case

Andrii:
* Improving libbpf for BTF (and in prior kernels)
* BTF to C converter
* next: using BTF to define bpf maps

=== Attendees ===
Alexei Starovoitov
Andrii Nakryiko
Augusto Caringi
Dan Siemon
Jesper Brouer
Richard Elling
Brenden Blanco
Jiong
Yonghong Song
Andy Gospodarek
Daniel Borkmann
Jakub Kicinski
Brendan Gregg
John Fastabend
Mauricio Vasquez
Paul Chaignon
Joe Stringer

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for joining the call today. As usual, here are my notes.

Thanks,
Brenden

=== Discussion ===

Yonghong:
- compile once run everywhere work continues
  - some prototypes for internal projects
  - some details to be presented at BPF microconference later this month
- implement helper to send signals to other processes in the system
- some bcc work on bpfd, patches to be reviewed
  - (bpfd is a remote bcc tool for low resource systems)

Matheus:
- macro support in bpftrace
- porting to new version of llvm pass manager
  - old version has some memory issues
- bpftrace issue #528
- request for jenkins support
  - Ubuntu 18.04 (4.15 or later)
  - ai for Brenden

Daniel:
- bpf global data support got merged
- cilium - masquerade support native in bpf

John:
- bounded loop work has resumed in llvm, hopefully something to review in a
  couple weeks
- some sockmap and ktls fixes

Martin:
- Socket local storage work
  - userspace looks like a regular map
  - a new helper to be implemented
  - local storage will be in the socket
  - memory charged to option memory of the socket

Brendan:
- Writing some advanced networking tools in bpftrace

Dan:
question about AF_XDP:
- is the intention that user mem can be large?
- 5-10k subscribers with ~10 packets each
  - may require some work to support hugepages
- some of the docs on the tx use case are somewhat lacking

=== Attendees ===
Brenden Blanco
Augusto Caringi
John Fastabend
Flavio Crisciani
Michael Savisko
Matheus
Dan Siemon
Marco Leogrande
Yonghong Song
Jakub Kicisnki
Paul Chaignon
Joe Stringer
Daniel Borkmann
Brendan Gregg
Martin Lau
Quentin Monnet
Saeed

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Jiong Wang]

Great, will have a look, thanks!

Regards,
Jiong

On 05/04/2019 07:45, Y Song wrote:

Hi, Jiong,

To follow up the iovisor meeting discussion, the below is my prototype
for an end_loop
instruction in llvm:
https://github.com/yonghong-song/llvm/commit/b83226772100317092cae6478229ed6ca3b9903c
The goal is to help verifier to just focus on these marked cases,
rejecting any other backedges.

Please let me and John know if you get some better idea for bounded
loop support in llvm/verifier.

Thanks,

Yonghong

On Wed, Apr 3, 2019 at 11:49 AM Brenden Blanco  wrote:

Hi All,

Thanks for the good discussion today! Below are my notes.

Thanks,
Brenden

=== Discussion ===

[...]

Yonghong:
* Compile once run anywhere work continues
   * bitfield handling bugs in IR/debuginfo

Daniel:
* Global support work continues
   * BTF side patches submitted to bpf mailing list
   * tests included

Jiong:
* 32 bit patch set
   * test methodology improvements
   * updated patches later in the week
   * some concerns around shifts, to be addressed in later improvements

Andrii:
* BTF and compile-once work integration
   to share prototype tool with Saeed

Brendan:
* Is there a tool to measure queue latency in qdisc->netdev layer?
   * debian/ubuntu are packaging bpftrace
   * except libbcc renamed to libbpf_cc
   * some issues with mixing iovisor's libbcc and debian's

Jesper:
* Fedora adding packaging support for libbpf

Alexei:
* systemd also adding support for libbpf - link to be provided?

=== Attendees ===
Brenden Blanco
Andril Nakryiko
Daniel Borkmann
Jesper Brouer
Jiong Wang
Marco Leogrande
Michael Savisko
Paul Chaignon
Quentin Monnet
Alexei Starovoitov
Saeed
Flavio
Rony
Jonathan Lemon
Brendan Gregg
Dan Siemon
Joe Stringer
John





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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Yonghong Song]

Hi, Jiong,

To follow up the iovisor meeting discussion, the below is my prototype
for an end_loop
instruction in llvm:
https://github.com/yonghong-song/llvm/commit/b83226772100317092cae6478229ed6ca3b9903c
The goal is to help verifier to just focus on these marked cases,
rejecting any other backedges.

Please let me and John know if you get some better idea for bounded
loop support in llvm/verifier.

Thanks,

Yonghong

On Wed, Apr 3, 2019 at 11:49 AM Brenden Blanco  wrote:
>
> Hi All,
>
> Thanks for the good discussion today! Below are my notes.
>
> Thanks,
> Brenden
>
> === Discussion ===
[...]
> Yonghong:
> * Compile once run anywhere work continues
>   * bitfield handling bugs in IR/debuginfo
>
> Daniel:
> * Global support work continues
>   * BTF side patches submitted to bpf mailing list
>   * tests included
>
> Jiong:
> * 32 bit patch set
>   * test methodology improvements
>   * updated patches later in the week
>   * some concerns around shifts, to be addressed in later improvements
>
> Andrii:
> * BTF and compile-once work integration
>   to share prototype tool with Saeed
>
> Brendan:
> * Is there a tool to measure queue latency in qdisc->netdev layer?
>   * debian/ubuntu are packaging bpftrace
>   * except libbcc renamed to libbpf_cc
>   * some issues with mixing iovisor's libbcc and debian's
>
> Jesper:
> * Fedora adding packaging support for libbpf
>
> Alexei:
> * systemd also adding support for libbpf - link to be provided?
>
> === Attendees ===
> Brenden Blanco
> Andril Nakryiko
> Daniel Borkmann
> Jesper Brouer
> Jiong Wang
> Marco Leogrande
> Michael Savisko
> Paul Chaignon
> Quentin Monnet
> Alexei Starovoitov
> Saeed
> Flavio
> Rony
> Jonathan Lemon
> Brendan Gregg
> Dan Siemon
> Joe Stringer
> John
>
> 
>

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for the good discussion today! Below are my notes.

Thanks,
Brenden

=== Discussion ===

Michael:
* https://github.com/savisko/katran/tree/xdp_off
* Mellanox presentation on XDP + Katran
  * offload tc XDP programs to hardware nic
  * Example application: Katran from Facebook
  * Control is implemented as a C++ library (example is open source)
  * Katran DP already implemented in XDP
* Parsing + extract flow ID
* lookup key generation
* counter update
* packet modified to forward to other IP
  * Accelerate marking of flows in hardware
* XDP metadata to pass mark field from hardware to xdp program
* struct xdp_md_mark {
__u32 mark)
  };
* if (mark_ptr + 1 <= data)
 markID = mark_ptr->mark;
* per-CPU XDP map to convert mark -> real flow information
  mark == 0 implies new flow
* original XDP slow-path has get_packet_dst() to create LRU mapping
* modified version uses perf event output to notify acceleration helper to
  install flow mark in hardware
  * perf results:
100 flows: 40+% performance improvements
10k flows: 0-50% performance improvements depending on #rx queues used
Software: 25Mpps
Hardware: 37-39Mpps
* considering changing implementation to mark real server instead of flow
  id, to reduce number of entries kept in L1 cache

Yonghong:
* Compile once run anywhere work continues
  * bitfield handling bugs in IR/debuginfo

Daniel:
* Global support work continues
  * BTF side patches submitted to bpf mailing list
  * tests included

Jiong:
* 32 bit patch set
  * test methodology improvements
  * updated patches later in the week
  * some concerns around shifts, to be addressed in later improvements

Andrii:
* BTF and compile-once work integration
  to share prototype tool with Saeed

Brendan:
* Is there a tool to measure queue latency in qdisc->netdev layer?
  * debian/ubuntu are packaging bpftrace
  * except libbcc renamed to libbpf_cc
  * some issues with mixing iovisor's libbcc and debian's

Jesper:
* Fedora adding packaging support for libbpf

Alexei:
* systemd also adding support for libbpf - link to be provided?

=== Attendees ===
Brenden Blanco
Andril Nakryiko
Daniel Borkmann
Jesper Brouer
Jiong Wang
Marco Leogrande
Michael Savisko
Paul Chaignon
Quentin Monnet
Alexei Starovoitov
Saeed
Flavio
Rony
Jonathan Lemon
Brendan Gregg
Dan Siemon
Joe Stringer
John

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

On Tue, Apr 2, 2019 at 10:48 AM Saeed Mahameed
 wrote:
>
> Hi Brenden,
>
> I am sending this on behalf of Michael Savisko, he is having some
> difficulties sending emails to the iovisor list.
Sending to the iovisor-dev mailer is gated by a signup requirement, in
order to reduce spam. The signup process should be pretty painless, I
believe it just requires going through an email validation step:
https://lists.iovisor.org/g/iovisor-dev/join
>
> Michael is working on real world use cases for XDP acceleration.
> He would like to present and discuss his work and analysis on
> accelerating Katran load balancer [1] via meta data offloads.
> He will need 10 minutes and will share some slides, i hope we can push
> this to tomorrow's meeting agenda.

Sounds good!
>
> Katran modified code is on Github:
> https://github.com/savisko/katran/tree/xdp_off
>
> [1] 
> https://code.fb.com/open-source/open-sourcing-katran-a-scalable-network-load-balancer/
> Thanks,
> Saeed.
>
> On Wed, Mar 20, 2019 at 3:32 PM Brenden Blanco  wrote:
> >
> > Hi all,
> >
> > Thanks for joining the discussion today. Here are the notes; however, this 
> > was
> > a longer discussion and I'm sure I missed some things.
> >
> > Cheers,
> > Brenden
> >
> > === Discussion ===
> >
> > Yonghong:
> > * Some internal BTF work
> > * Compiler support for static variables
> > * Some compile-once-run-everywhere work
> > * Looking for help with issues regarding libbpf packaging/dependencies
> >   * Issue to continue offline, not concluded on the call
> > * Issue related to function->function call in bcc and compiler optimizations
> >   * Jiong offers to debug the codegen using 32 bit mode
> >
> > Saeed:
> > * XDP driver statistics standardization
> >   * All drivers run same entry point for xdp progs
> > * Why not account stats here?
> > * Even though xdp program can implement its own statistics
> > * Many drivers are already paying stats accounting cost
> >   * Just remove unused stats from driver?
> > * Stats may be used in debugging, but FB for instance is guarding with
> >   static key, wouldn't want extra stats on by default
> > * Allocating resources for tx queue/redirect?
> >   * Is there a better way to allocate resources when it isn't known that a
> > program will need queues
> >   * One approach is to attach dummy bpf program
> >   * Resource allocation point when configuring devmap?
> > * Seems like a clean enough solution, doesn't solve all cases but moves 
> > the
> >   ball forward
> > * BTF metadata structure registration
> >   * Should be queryable from userspace, don't yet have an API for that
> >   * Netlink vs syscall?
> > * No silver bullet for all use cases
> >   * Hesitation for creating a new object to describe existing objects (bpf
> > progs, maps)
> > * BTF is metadata conceptually different from maps, progs
> > * ethtool? unlikely due to lack of code ownership
> > * For buffers, something like devlink is more appropriate
> > * For BTF, bpf() syscall works
> > * BTF for statistics description (ethtool replacement?)
> >
> > Daniel:
> > * verification of static data is working, patches coming soon
> >
> > === Attendees ===
> > Brenden Blanco
> > Michael Savisko
> > Alexei Starovoitov
> > Daniel Borkmann
> > Jakub Kicinski
> > Neerav Parikh
> > Paul Chaignon
> > Saeed
> > Marco Leogrande
> > Jiong Wang
> > Andrii Nakryiko
> > Yonghong Song
> > William Tu
> > Joe Stringer
> > John
> > Maciej Fijalkowski
> > Martin Lau
> > Mauricio Vasquez
> > Piotr Raczynski
> > Quillian Rutherford
> >
> > 
> >

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Saeed Mahameed]

Hi Brenden,

I am sending this on behalf of Michael Savisko, he is having some
difficulties sending emails to the iovisor list.

Michael is working on real world use cases for XDP acceleration.
He would like to present and discuss his work and analysis on
accelerating Katran load balancer [1] via meta data offloads.
He will need 10 minutes and will share some slides, i hope we can push
this to tomorrow's meeting agenda.

Katran modified code is on Github:
https://github.com/savisko/katran/tree/xdp_off

[1] 
https://code.fb.com/open-source/open-sourcing-katran-a-scalable-network-load-balancer/
Thanks,
Saeed.

On Wed, Mar 20, 2019 at 3:32 PM Brenden Blanco  wrote:
>
> Hi all,
>
> Thanks for joining the discussion today. Here are the notes; however, this was
> a longer discussion and I'm sure I missed some things.
>
> Cheers,
> Brenden
>
> === Discussion ===
>
> Yonghong:
> * Some internal BTF work
> * Compiler support for static variables
> * Some compile-once-run-everywhere work
> * Looking for help with issues regarding libbpf packaging/dependencies
>   * Issue to continue offline, not concluded on the call
> * Issue related to function->function call in bcc and compiler optimizations
>   * Jiong offers to debug the codegen using 32 bit mode
>
> Saeed:
> * XDP driver statistics standardization
>   * All drivers run same entry point for xdp progs
> * Why not account stats here?
> * Even though xdp program can implement its own statistics
> * Many drivers are already paying stats accounting cost
>   * Just remove unused stats from driver?
> * Stats may be used in debugging, but FB for instance is guarding with
>   static key, wouldn't want extra stats on by default
> * Allocating resources for tx queue/redirect?
>   * Is there a better way to allocate resources when it isn't known that a
> program will need queues
>   * One approach is to attach dummy bpf program
>   * Resource allocation point when configuring devmap?
> * Seems like a clean enough solution, doesn't solve all cases but moves 
> the
>   ball forward
> * BTF metadata structure registration
>   * Should be queryable from userspace, don't yet have an API for that
>   * Netlink vs syscall?
> * No silver bullet for all use cases
>   * Hesitation for creating a new object to describe existing objects (bpf
> progs, maps)
> * BTF is metadata conceptually different from maps, progs
> * ethtool? unlikely due to lack of code ownership
> * For buffers, something like devlink is more appropriate
> * For BTF, bpf() syscall works
> * BTF for statistics description (ethtool replacement?)
>
> Daniel:
> * verification of static data is working, patches coming soon
>
> === Attendees ===
> Brenden Blanco
> Michael Savisko
> Alexei Starovoitov
> Daniel Borkmann
> Jakub Kicinski
> Neerav Parikh
> Paul Chaignon
> Saeed
> Marco Leogrande
> Jiong Wang
> Andrii Nakryiko
> Yonghong Song
> William Tu
> Joe Stringer
> John
> Maciej Fijalkowski
> Martin Lau
> Mauricio Vasquez
> Piotr Raczynski
> Quillian Rutherford
>
> 
>

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi all,

Thanks for joining the discussion today. Here are the notes; however, this was
a longer discussion and I'm sure I missed some things.

Cheers,
Brenden

=== Discussion ===

Yonghong:
* Some internal BTF work
* Compiler support for static variables
* Some compile-once-run-everywhere work
* Looking for help with issues regarding libbpf packaging/dependencies
  * Issue to continue offline, not concluded on the call
* Issue related to function->function call in bcc and compiler optimizations
  * Jiong offers to debug the codegen using 32 bit mode

Saeed:
* XDP driver statistics standardization
  * All drivers run same entry point for xdp progs
* Why not account stats here?
* Even though xdp program can implement its own statistics
* Many drivers are already paying stats accounting cost
  * Just remove unused stats from driver?
* Stats may be used in debugging, but FB for instance is guarding with
  static key, wouldn't want extra stats on by default
* Allocating resources for tx queue/redirect?
  * Is there a better way to allocate resources when it isn't known that a
program will need queues
  * One approach is to attach dummy bpf program
  * Resource allocation point when configuring devmap?
* Seems like a clean enough solution, doesn't solve all cases but moves the
  ball forward
* BTF metadata structure registration
  * Should be queryable from userspace, don't yet have an API for that
  * Netlink vs syscall?
* No silver bullet for all use cases
  * Hesitation for creating a new object to describe existing objects (bpf
progs, maps)
* BTF is metadata conceptually different from maps, progs
* ethtool? unlikely due to lack of code ownership
* For buffers, something like devlink is more appropriate
* For BTF, bpf() syscall works
* BTF for statistics description (ethtool replacement?)

Daniel:
* verification of static data is working, patches coming soon

=== Attendees ===
Brenden Blanco
Michael Savisko
Alexei Starovoitov
Daniel Borkmann
Jakub Kicinski
Neerav Parikh
Paul Chaignon
Saeed
Marco Leogrande
Jiong Wang
Andrii Nakryiko
Yonghong Song
William Tu
Joe Stringer
John
Maciej Fijalkowski
Martin Lau
Mauricio Vasquez
Piotr Raczynski
Quillian Rutherford

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Saeed Mahameed]

Hi Guys,

My agenda for next meeting:

1) unifying and centralizing XDP statistics accounting [1].
2) XDP resource management, User API [2].
3) XDP meta data via btf (in kernel BTF registration).
4) all of the above issues share one common problem, which is the lack
of a unified user interface
without it, We really can't make a real progress.

I just sent a proposal [3] for away to achieve the unified interface,
please look it up and let me know your thoughts.
[1] 
https://github.com/xdp-project/xdp-project/blob/master/xdp-project.org#statistics-per-xdp-action
[2] 
https://github.com/xdp-project/xdp-project/blob/master/xdp-project.org#better-ndo_xdp_xmit-resource-management
[3] Subject: "[RFC][Proposal] BPF Control MAP"

Thanks,
Saeed

On Wed, Mar 6, 2019 at 12:51 PM Brenden Blanco  wrote:
>
> Hi All,
>
> Thank you for joining the call today. Here are my notes from the discussion.
>
> Thanks,
> Brenden
>
> === Discussion ===
> Brenden:
> * Plan to tag release to coincide with kernel 5.0
>
> Brendan:
> * Speaking this weekend at SCaLE in Los Angeles
>
> Yonghong:
> * LLVM work
>  * compile once - run anywhere WIP
>  * support for static variables
>
> Daniel:
> * Global data support work in kernel continues
> * Ability to lock maps as read-only
> * bugfixes after merge window
>
> Alexei:
> * Some thoughts on future work of BPF
>  * especially with introduction of BTF
>  * overall needs concerted effort to improve debuggability
>  * BTF for programs itself with source/type/layout information
>  * structures for maps and global data
>  * suggest to always require type information
>(already turned on by default in bcc and supported by llvm)
>  * Some extra hoops to jump through for driver embedded BPF
>  * to be enabled with a sysctl
>  * kernel support is ready
>  * some long tail of support - e.g. systemd has raw assembly BPF
>  * kconfig option - eventual deprecation
>  * if kernel is default strict, llvm should automatically emit BTF as well
> * memcg accounting patch status?
>  * Daniel - still being worked on
>  * proposal to enable the same accounting for verifier memory
>  * helps to enable verifier multithreading
>
> Jakub:
> * question regarding global data atomicity
>  * Daniel - requires read once / write once instructions to work properly
>  * some todo work on documentation, interpreter + jit implementations
>  * depends on architecture (machine word size guarantees only)
>
> Jesper:
> * which llvm release supports BTF
>  * landed in December - will be in 8.0, better in 9.0
> * working on tutorial for xdp at netdev
>  * https://www.netdevconf.org/0x13/session.html?tutorial-XDP-hands-on
>  * soliciting feedback
>   * https://github.com/xdp-project/xdp-tutorial/
>
> Saeed:
> * request to devote some time in the next meeting to iron out some XDP issues
>  * please send an agend in reply to the reminder email before next call
>  * prepare discussion over email in between time
>
> === Attendees ===
> Alexei Starovoitov
> Marco Leogrande
> Mauricio Vasquez
> Paul Chaignon
> Brenden Blanco
> Jiong Wang
> Yonghong Song
> Daniel Borkmann
> Jesper Brouer
> Quentin Monnet
> Dan Siemon
> Jakub Kicinski
> Saeed
> John
> Yutaro
>
> 
>

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thank you for joining the call today. Here are my notes from the discussion.

Thanks,
Brenden

=== Discussion ===
Brenden:
* Plan to tag release to coincide with kernel 5.0

Brendan:
* Speaking this weekend at SCaLE in Los Angeles

Yonghong:
* LLVM work
 * compile once - run anywhere WIP
 * support for static variables

Daniel:
* Global data support work in kernel continues
* Ability to lock maps as read-only
* bugfixes after merge window

Alexei:
* Some thoughts on future work of BPF
 * especially with introduction of BTF
 * overall needs concerted effort to improve debuggability
 * BTF for programs itself with source/type/layout information
 * structures for maps and global data
 * suggest to always require type information
   (already turned on by default in bcc and supported by llvm)
 * Some extra hoops to jump through for driver embedded BPF
 * to be enabled with a sysctl
 * kernel support is ready
 * some long tail of support - e.g. systemd has raw assembly BPF
 * kconfig option - eventual deprecation
 * if kernel is default strict, llvm should automatically emit BTF as well
* memcg accounting patch status?
 * Daniel - still being worked on
 * proposal to enable the same accounting for verifier memory
 * helps to enable verifier multithreading

Jakub:
* question regarding global data atomicity
 * Daniel - requires read once / write once instructions to work properly
 * some todo work on documentation, interpreter + jit implementations
 * depends on architecture (machine word size guarantees only)

Jesper:
* which llvm release supports BTF
 * landed in December - will be in 8.0, better in 9.0
* working on tutorial for xdp at netdev
 * https://www.netdevconf.org/0x13/session.html?tutorial-XDP-hands-on
 * soliciting feedback
  * https://github.com/xdp-project/xdp-tutorial/

Saeed:
* request to devote some time in the next meeting to iron out some XDP issues
 * please send an agend in reply to the reminder email before next call
 * prepare discussion over email in between time

=== Attendees ===
Alexei Starovoitov
Marco Leogrande
Mauricio Vasquez
Paul Chaignon
Brenden Blanco
Jiong Wang
Yonghong Song
Daniel Borkmann
Jesper Brouer
Quentin Monnet
Dan Siemon
Jakub Kicinski
Saeed
John
Yutaro

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for dialing in to the meeting today. Here are my notes from the
discussion.

Thanks,
Brenden

=== Discussion ===
Alexei:
- Discussion with some kernel devs regarding BPF memory model
  - some documentation to be done
  - (currently avoiding uapi enforcement on content of bpf program itself)
  - introduce standard header file for bpf programs to include
- add read_once, write_once primitive
- llvm will understand this
  - 64 bit jit must implement these instructions

LSFMM will have a BPF track
 - CFP closes this Friday, send your proposals if you have them
 - Or send an email if you simply wish to attend

Saeed:
- LPC discussion followup - metadata parsing in hardware
  - way to notify/raise events userspace of new flow marks detected and trigger
injection of tc rule?
- use perf ring buffer, available in kernel samples/

Brendan:
- bpftrace function tracing use case in java
  - needs couple fixes
- uprobe to be able to attach heap locations instead of inode-only
- tell c2 compiler to pause moving functions around
- looking for ways to get past libc/libpthread backtrace walking (usually
  compiled without frame pointer)
  - hoping for Intel LBR support, but not available in many cloud VMs yet

=== Attendees ===
Brenden Blanco
Andrii Nakryiko
Dan Siemon
Marco Leogrande
Jesper Brouer
Jerome Marchand
Tom Stellard
Jakub Kicinski
Bjorn Topel
Martin Lau
Andy Gospodarek
Paul Chaignon
Jiong Wang
Alexei Starovoitov
Daniel Borkmann
Saeed
Quentin Monnet
Mauricio Vasquez
Matheus Marchini
Joe Stringer
Florian
Brendan Gregg

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thank you for joining us on the call today. As usual, here are the notes.

-Brenden

=== Discussion ===

Yonghong:
- working on libbpf features
- working on btf support in bcc
  - need to use upstream libbpf apis, in process of upstreaming/converting
  - llvm support is working (9.0)

Joe:
- cilium: getting static data to be updated from elf section
  - allows iproute2 to fetch 32bit values from data section
  - populate instructions that refer to the data at load time
  - different data sizes not yet supported/tested
  - would like to incorporate global data support on the kernel side

Martin:
- bpf socket and tc socket patches posted
  - what happens with sockets in timewait state?
  - is there a usecase for such sockets? not at this moment, but still under
discussion

Discussion about allocating sockopt storage for bpf use cases

John:
- Discussion about ipsec integration with bpf
- bpf program to compute hash key instead of setting up ipsec rules
  - currently in idea phase only

Daniel:
- cilium ipvlan support nearing completion

Brendan:
- bpftrace integration/improvements making nice progress

=== Attendees ===
Brenden Blanco
Yonghong Song
Marco Leogrande
Jesper Brouer
Joe Stringer
Mauricio Vasquez
Quentin Monnet
Daniel Borkmann
Jiong Wang
Martin Lau
Brendan Gregg
John Fastabend

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Jiong Wang]

On 24/01/2019 02:33, Brenden Blanco wrote:

Jiong:
* respin jmp32 patch set - v2
   - implementation in working state
   - isa for subregister looking good
   - codegen giving smaller results (num of instructions)
   - will resend patch set after fixing test failure


Finished re-spin and rebased on top of latest bpf-next.

My set will potentially conflict with the following three other bpf-next
pending patches/sets on selftests Makefile and test_verifier.c:
  - Stanislav's LLVM_READELF change on Makefile.
  - Alexei's spin_lock change on test_verifier.c.
  - Jakub's test_verifier.c refactor on test_verifier.c.

The conflict should be easy to resolve. For test_verifier.c, my set just
adds new tests at the end of the test array. I will send out v3 shortly.

Regards,
Jiong


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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for dialing in to the call today. Here are notes from the discussion.

Thanks,
Brenden

=== Discussion ===

Alexei:
* Spinlock patches being worked on
* Proposal to standardize the BPF ELF format/api to that used by libbpf/bpftool
  - First user might be iproute2 conversion
  - Should support multi-language bindings (go)
  - Approved

Brenden:
* Tagged bcc release

Yonghong:
* bringing libbpf into bcc
  - few related bugs
* bringing BTF support into bcc - WIP
  - issue on getting remapped file (from compilation stage) info into bcc
  - getting btf type during map creation in right order in bcc...needs some
thought
* build id support added - first user in trace.py

Jiong:
* respin jmp32 patch set - v2
  - implementation in working state
  - isa for subregister looking good
  - codegen giving smaller results (num of instructions)
  - will resend patch set after fixing test failure

John:
* patches to be sent out for sockmap and ktls
* the parser in the filter on the ktls rx side needs some work
  - there are some edge cases between ktls and other parsers

Jakub:
* refactoring test cases for verifier improvements

Daniel:
* Helping to refactor/review test verifier code
  - splitting up tests by category
* Cilium work to add in second datapath (ipvlan based)

=== Attendees ===
Brenden Blanco
Alexei Starovoitov
Jakub Kicinksi
Martin Lau
Mauricio Vasquez
Quentin Monnet
Dan Siemon
Daniel Borkmann
Jesper Brouer
Andy Gospodarek
Maciej Fijalkowski
Yonghong Song
John F
Paul Chaignon

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[William Tu]

On Wed, Jan 9, 2019 at 11:59 AM Brenden Blanco  wrote:
>
> Hi All,
>
> Thanks for joining the call today after a short holiday hiatus. Below are my
> notes from the call.
>
> === Discussion ===
> Brenden
> * Adopted new project kubectl-trace into github.com/iovisor from the author's
>   (@fntlnz) personal github
>   - Adds support for running bpftrace as a 'kubectl trace' command in a
> kubernetes environment
>   - Presented at Kubecon 2018:
> 
> https://kccna18.sched.com/event/GrYw/ebpf-powered-distributed-kubernetes-performance-analysis-lorenzo-fontana-influxdata
>   - Please give it a spin and contribute/comment on
> github.com/iovisor/kubectl-trace
> * Nice work Lorenzo!
>
> Yonghong
> * funcinfo and line info merged BTF support merged into kernel
> * clang debug info for bpf
>   - use -g from clang to generate such info that gets passed along to BTF
>   - some blocking issues to bring this feature into bcc
> - btf info not being handled properly by dynamic linker
> * bcc plan to release by end of the week to coincide with kernel release
> * wip: add 128 bit int support
>
> Brendan
> * Compiler errors with linux 5.0-rc (asm goto)
> * Working on documentation and packaging for bpftrace
>   - lots of small bugs to fix marching towards 1.0
>
> Alexei
> * Proposing dates and format for BPF/IO Visor specific technical miniconf in 
> the
>   springtime
>   - March-May timeframe
>   - 2 days?
>
> William
> * Adding AF_XDP support to vSphere driver

Sorry, I mean AF_XDP for veth driver.
Thank you
William


>
>
> === Attendees ===
> Brenden Blanco
> Quentin Monnet
> Jakub Kicinski
> Alexei Starovoitov
> Jiong Wang
> Maciej Fijalkowski
> William Tu
> Yonghong Song
> Brendan Gregg
> Daniel Borkmann
> Martin Lau
> Neerav Parikh
>
> 
>

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for joining the call today after a short holiday hiatus. Below are my
notes from the call.

=== Discussion ===
Brenden
* Adopted new project kubectl-trace into github.com/iovisor from the author's
  (@fntlnz) personal github
  - Adds support for running bpftrace as a 'kubectl trace' command in a
kubernetes environment
  - Presented at Kubecon 2018:

https://kccna18.sched.com/event/GrYw/ebpf-powered-distributed-kubernetes-performance-analysis-lorenzo-fontana-influxdata
  - Please give it a spin and contribute/comment on
github.com/iovisor/kubectl-trace
* Nice work Lorenzo!

Yonghong
* funcinfo and line info merged BTF support merged into kernel
* clang debug info for bpf
  - use -g from clang to generate such info that gets passed along to BTF
  - some blocking issues to bring this feature into bcc
- btf info not being handled properly by dynamic linker
* bcc plan to release by end of the week to coincide with kernel release
* wip: add 128 bit int support

Brendan
* Compiler errors with linux 5.0-rc (asm goto)
* Working on documentation and packaging for bpftrace
  - lots of small bugs to fix marching towards 1.0

Alexei
* Proposing dates and format for BPF/IO Visor specific technical miniconf in the
  springtime
  - March-May timeframe
  - 2 days?

William
* Adding AF_XDP support to vSphere driver


=== Attendees ===
Brenden Blanco
Quentin Monnet
Jakub Kicinski
Alexei Starovoitov
Jiong Wang
Maciej Fijalkowski
William Tu
Yonghong Song
Brendan Gregg
Daniel Borkmann
Martin Lau
Neerav Parikh

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Thanks all for joining in to the call today. As usual, here are my notes.

=== Discussion ===

Jiong:
Continuing work on jmp32
- some work on verifier side
- needs to work on test support - new test mode with alu 32 option
- LLVM in alu 32 mode caused some verifier rejections...investigating

Yonghong:
Some BTF related bug cleanup
Working on LLVM -> BCC -> bpf() functionality prototype
- Some dependencies on LLVM/clang patch integration...may cause slowdown
Planning to integrate libbpf into libbcc
- More updates to be sent to mailing list in next couple weeks

William:
Continuing OVS/AF_XDP work
- Presenting at OVS conf in San Jose
- Some further use cases to be presented (tunneling, virtual port)

Jakub:
Attempted to package bpftool in debian, but ran into gplv3 libbfd linking issue
- Will attempt to dual-license and ask permission from contributors, check email
- Some concerns about size of library

Jesper:
Page pool patches are in a working state
- Working through prototype code on an arm64 board
- Some early integration with the mlnx driver that uses page pools as well

** For version-controlled collaboration on XDP related topics, join Jesper and
  others using the https://github.com/xdp-project/xdp-project repo

John:
sockmap/ktls work improvements to enable Cilium use cases

Joe:
looking into feedback on patches related to signed values


=== Attendees ===
Alexei Starovoitov
Andy Gospodarek
Augusto Caringi
David Beckett
Jakub Kicinski
Jesper Brouer
John Fastabend
Yonghong Song
Paul Chaignon
Paul Jardetzky
Quentin Monnet
William Tu
Yifeng Sun
Neerav Parikh
Brenden Blanco

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for joining in to the discussion today. Below are my notes from
the call. Hope everyone is looking forward to good discussions at the
LPC BPF track in Vancouver in two weeks! Since that overlaps with the
usual IO Visor call, we will have our next meeting in 4 weeks time
instead.

Thanks,
Brenden

=== Discussion ===

Brenden:
* tracking some buildbot failures
* will look at adding fedora 29 target
* to tag 0.8.0 soon

Yonghong:
* updated kernel headers
* working on llvm internals for BTF support

Alexei:
* for those presenting at LPC/bpf track, please send rough draft of slides by
  tomorrow
* significant effort to do deduplication of dwarf->BTF of vmlinux symbols:
  300MB->2MB
* feature: atomic spin lock/unlock callable from bpf programs
  * 1 lock only
  * no helper calls within critical section
  * BTF will be mandatory for such programs
  * more to be presented at plumbers

Daniel:
* Some security fixes
* LPC slides

John:
* Work on paper/slides for LPC
* Sockmap support is enabled in Cilium!
  * (mellanox?) working to add upstream support in openssl for kTLS + sockmap

Jakub:
* working on getting libbpf packaged separately and released by distros
  * FB has external mirror github.com/libbpf/libbpf


=== Attendees ===
Brenden Blanco
Paul Chaignon
Dan Siemon
Nic Viljoen
Alexei Starovoitov
Andy Gospodarek
Jakub Kicinski
Daniel Borkmann
Yonghong Song
Mauricio Vasquez
JohnF
Joe Stringer
Quentin Monnet
William Tu
Quillian Rutherford

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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Yonghong Song]

On Wed, Oct 3, 2018 at 11:26 AM Brenden Blanco  wrote:
>
> Hi all,
>
> Thanks for joining the call this week. Here are my notes of the items 
> discussed.
>
> -Brenden
>
> === Discussion ===
>
> Yonghong:
> - BTF support in LLVM WIP
>   - prototype is approaching functionality
>   - to post to llvm mailing list soon (enabled through -g -target=bpf mode)

The link to the llvm patch which generates .BTF and .BTF.ext sections:
https://reviews.llvm.org/D52950

>
> William:
> - OVS + AF_XDP performance improvements
>   - more batching on tx side
>   - add more asynchronous logic
>   - goes from 5Mpps -> 14Mpps forwarding
> - tested ixgbe AF_XDP v2 support - seems to be working
>
> Daniel:
> - kTLS and sockmap integration WIP with John
>   - planning to post this week
> - bpf plumbers track submissions is closed
>
> JohnF:
> - Working on Cilium pieces for kTLS+sockmap
>
> Joe:
> - Socket lookup helpers were merged this week
>
> Jesper:
> - working on XDP paper with John and Daniel
> - Gave talk in Paris @Kernel Recipes
>   - 
> http://people.netfilter.org/hawk/presentations/KernelRecipes2018/XDP_Kernel_Recipes_2018.pdf
>
> Mauricio:
> - Working to address review comments this week on bpf queue and stackmap
>
> === Attendees ===
> Brenden Blanco
> Yonghong Song
> Jakub Kicinski
> Mauricio Vasquez
> JohnF
> Daniel Borkmann
> Joe Stringer
> William Tu
> Jesper Brouer
> Jiong Wang
> Nic Viljoen
> Quentin Monnet
>
> 
>

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi all,

Thanks for joining the call this week. Here are my notes of the items discussed.

-Brenden

=== Discussion ===

Yonghong:
- BTF support in LLVM WIP
  - prototype is approaching functionality
  - to post to llvm mailing list soon (enabled through -g -target=bpf mode)

William:
- OVS + AF_XDP performance improvements
  - more batching on tx side
  - add more asynchronous logic
  - goes from 5Mpps -> 14Mpps forwarding
- tested ixgbe AF_XDP v2 support - seems to be working

Daniel:
- kTLS and sockmap integration WIP with John
  - planning to post this week
- bpf plumbers track submissions is closed

JohnF:
- Working on Cilium pieces for kTLS+sockmap

Joe:
- Socket lookup helpers were merged this week

Jesper:
- working on XDP paper with John and Daniel
- Gave talk in Paris @Kernel Recipes
  - 
http://people.netfilter.org/hawk/presentations/KernelRecipes2018/XDP_Kernel_Recipes_2018.pdf

Mauricio:
- Working to address review comments this week on bpf queue and stackmap

=== Attendees ===
Brenden Blanco
Yonghong Song
Jakub Kicinski
Mauricio Vasquez
JohnF
Daniel Borkmann
Joe Stringer
William Tu
Jesper Brouer
Jiong Wang
Nic Viljoen
Quentin Monnet

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for joining the call today. Here are my notes!

Cheers,
Brenden

=== Discussion ===

Brenden:
* 0.7.0 tag released to support 4.18
* Flaky test on fc26 - usdt3 - monitor and perhaps relax contraints in test

Yonghong:
* Discussing API for BTF support in kernel
  * prototyping currently the kernel interface
  * will need a few more weeks
* Introspection improvements
  * Duplicating some ip/tc functionality into bpftool
  * Reason: want one integrated tool for all bpf introspection
  * Some debate about what the value of duplicating code is
* Need to avoid too many tools
* Lots of non-net users: cgroups, tc, xdp, perf
  * dual license libbpf to converge the code?

Alexei:
* bpf-next opened, swamped with code reviews

Jiong:
* 32 bit support
  * standalone flow control analyzer in progress
  * will try to remove extra config flags

William:
* AF_XDP for OVS
  * without zero copy driver, perf tests
  * > 3Mpps rx so far
  * working on port->port forwarding, with memcpy
  * needs zero-copy driver to improve tx speeds
  * will try with i40e driver

=== Attendees ===
Brenden Blanco
Jakub Kicinski
Jiong Wang
Yonghong Song
Jesper Brouer
Alexei Starovoitov
Joe Stringer
Brendan Gregg
William Tu
JohnF

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Thanks all for joining the call today. As usual, here are my notes.

-Brenden

=== Discussion ===
Yonghong:
* Internal discussions for BTF related work
  * adding information to jit instructions
  * debug annotations
* Introspection for networking
  * Device walker, qdisc for finding xdp/bpf programs
* Tag release after .increment bug is fixed

Alexei:
* Trying to improve introspection of bpf
  * Add LLVM class for emitting BTF debug info
  * Possible standalone LLVM tool for converting dwarf->btf
  * pahole fixes coming soon
* plan to use this tool for annotating kernel build to avoid heavy LLVM
  dependency

William:
* AFXDP patch sent last week for OVS
  * Performance still lagging due to extra memcpy
  * Next iteration will try zerocopy mode
  * Despite kasan, still seeing death due to oom-killer
* Intel folks helping with debug

Daniel:
* Fixes for tcp ulp, sockmap, xdp redirect with tailcalls
* Work continues on sockmap, KTLS
* CFP is open for BPF track at Plumbers!

John:
* KTLS and sockmap work
  * BPF in KTLS working, cleaning up patches for submission
* Bounded loop work possibly to be discussed at LPC

Bjorn:
* AFXDP zerocopy patches to be submitted when bpf-next opens
  * ixgbe/i40e patches to be included, or separately through intel tree


=== Attendees ===
Brenden Blanco
Quentin Monnet
Sandipan
Daniel Borkmann
Josh
Kuba Kicinski
William Tu
Jiong Wang
Alexei
Yifeng Sun
Yonghong Song
Bjorn Topel
Brendan Gregg
John F
Mauricio Vasquez

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco]

Hi All,

Thanks for attending the meeting today. As usual, here are my notes.

=== Discussion ===

Brenden:
- working on fc28 packaging
  - pr available
  - includes some python3 fixes
  - not to be included in next release tag :(
- v0.6.0 tagged

Yonghong:
- Some rewriter changes, working with Paul
- 4.17 changed some syscall parameters
  - some fixes in bcc, when __syscall prefix is seen
- tracepoint structure bugfix
- introduce option to change license option

Alexei:
- bcc release schedule
  - want to release within short timeframe of kernel release
  - have tried to keep backwards compatible, but still highly dependent on
kernel

Saeed:
- xdp offloads update
  - working on examples for using the new api/metadata
  - perf numbers to be published after that
- currently experimenting with dynamic hw metadata
  - e.g.: vlan, csum complete, hash, flow tag
- can hardware provide offsets to tcp data as a new metadata field?

Okash:
- BTF
  - some WIP patches for pretty printing maps, currently for array maps

John:
- sockhash fixes from fuzzbot
  - bugs in locking and ipv6 ports
- Working on RFC for bounded loop support
  - need to expand from finding loop induction vars to all induction vars
  - llvm likes to build nested loops, and always jumps with a conditional in
the middle, makes finding loop induction variables hard
  - also important to add overflow checks
  - possible to modify llvm to make verifying easier?
- annotations? how to rely on them for safety...
- introduce rep counter
- more crazy ideas discussed - pass SSA, dom tree info to verifier

Brendan:
- bcc+btf support?
  - not yet, still working on dwarf->btf converter
  - pahole has some gaps to be able to convert kernel dwarf
- probably good enough though


=== Attendees ===
Brenden Blanco
Opher
Bjorn Topel
Marco Leogrande
Martin Lau
Nic Viljoen
Saeed
Jakub Kicinski
George
Jesper Brouer
Alexander Duyck
Quentin Monnet
Daniel Borkmann
William Tu
Yonghong Song
Brendan Gregg
Yifeng Sun
John Fastabend
Okash

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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi all,

Thanks for joining in the discussion today. As usual, here are my notes.

-Brenden

=== Discussion ===

Brenden:
- Adding fedora 28 buildbot/packages
   - debugging some test failures
- Tag release 0.7.0 after that

Yonghong:
- Some more python3 fixes
- Some rewriter changes, breakages
- Tool to do introspection for kprobe, uprobe

John:
- Working for certain classes of loops
   - some caveats with searching for loop variable declarations
   - only considers first order induction variables

Bjorn:
- some concerns about descriptor format
   - target to update next week
- to disable support in the meantime
   - kconfig/uapi header removal?
   - return not supported for socket options in meantime
- support for brcm, mlnx next merge window

Saeed:
- for AF_XDP, starting work on xdp offload for metadata/flow-mark concept
   - when loading xdp program, request specific offloads
 - e.g. vlan stripping, modifies headroom calculation
 - flow hash in metadata, avoid caching packet before forwarding w/
cpuhash
   - to come up with a proposal next week

=== Attendees ===
Brenden Blanco
Alexei Starovoitov
Andy Gospodarek
Bjorn Topel
Brendan Gregg
Jesper Brouer
Magnus
Yonghong Song
Quentin Monnet
Saeed
Kuba Kicinski
Alexander Duyck
JohnF
William Tu
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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Jiong Wang via iovisor-dev]

On 17/05/2018 05:38, Brenden Blanco via iovisor-dev wrote:

Hi All,

Thanks for attending the meeting today. As usual, here are my notes.

=== Discussion ===
Bjorn
- AF_XDP zero copy implementation RFC on netdev
- some uapi concerns, may need to back out changes
- but, over next couple weeks before merge window, discuss and improve in
  hopes of merging
- clean up non-intel code, respin, leave out i40e patches at the end
- separate i40e cleanup spin
- bcm may try to join as 2nd vendor to flesh out uapi
- some discussion of common code organization
- xdp in separate file helps backporting

Yonghong
- some python3 fixes
- proposals for improved container support
- rewriter complexity increasing
- tracing event introspection

Martin
- BTF id landed
- working on bpftool support
- still using pahole to convert dwarf
- still unclear how integration with llvm will look

Jiong
- dominator tree info RFCs pushed
- significant mem/exec time costs to run (e.g. 2x more, 3x slower)


Just for the record, if I listened correctly, John proposed to introduce
a switch for the new CFG infrastructure, i.e, we keep the exisiting DFS
based check_cfg, the new CFG code will only be enabled when check_cfg
detected a loop and wants know whether it is bounded, by this we could
avoid extra mem/exec time cost on programs that don't have loop.

Regards,
Jiong


John
- induction variable tracking in progress
- next: min/max value tracking
both: to work on topic branch under bpf-next

William
- tried workaround from Yonghong
- still need to dig into root cause

Joe
- implementation of sock lookup going through iterations
- concerns over locking in bpf being a leaky implementation detail


=== Attendees ===
Brenden Blanco
Alexei Starovoitov
Bjorn Topel
Daniel Borkmann
Jesper Brouer
Jiong Wang
Magnus Karlsson
Quentin Monnet
Joe Stringer
Andy Gospodarek
Ferris
Brendan Gregg
Jakub Kicinski
William Tu
Yonghong Song
Alexander Duyck
Sandipan
John F
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Re: [iovisor-dev] minutes: IO Visor TSC / Dev Meeting

[Björn Töpel via iovisor-dev]

2018-05-03 1:39 GMT+02:00 Brenden Blanco via iovisor-dev
:
> Hi All,
>
> Thanks for joining the discussion today. As usual, here are my notes.
>
> -Brenden
>
> === Discussion ===
>
> John:
> - sockmap fixes pushed
>   - fixed broken tests
> - sockmap hash impl next
> - bounded loop rfc making progress
> - cilium code using sockhash almost finished as well
>
> Yonghong:
> - python3 test cleanup
>   - except memleak tool
> - raw tracepoint support in bcc
>   - runqlat tool
>   - bio tracing
>   - more precise than kprobes
> - next work: introspection - bpf trace program in perf
>
> Martin:
> - BTF id patch WIP
>   - BTF id -> BTF map
> - next: support function pointer type in BTF
>
> William:
> - moving bpf tunnel example -> selftest
> - hitting issue with long running test tunnel cases
>   - try enabling kasan to debug
> - verifier issue bugfix (ctx + constant arithmetic) WIP
>
> Daniel:
> - finalizing removal of some inst from jit
> - few bugfixes in x86 jit
>
> Alexei:
> - AF_XDP patches being reviewed, looks ok
>

Unfortunately, I missed the call. Appreciate that AF_XDP was took into
discussion! Thanks for the review!

> Jesper:
> - Testing AF_XDP patches currently
>   - no driver changes needed with xdp_redirect
>   - driver changes still needed for zerocopy
>   - intel: 12mpps, mlnx: 9mpps drop
>

Again, thanks a lot for spending time on the AF_XDP patchset!


Cheers,
Björn

> Brendan:
> - CFP for USENIX LISA in October, Nashville TN
>
> === Attendees ===
> Brenden Blanco
> Alex Reece
> Jakub Kicinski
> Martin Lau
> Quentin Monnet
> Sandipan
> Jiong Wang
> William Tu
> Alexei Starovoitov
> Alexander Duyck
> John Fastabend
> Jesper Brouer
> Daniel Borkmann
> Yonghong Song
> Brendan Gregg
> Ferris
> ___
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Re: [iovisor-dev] minutes: IO Visor TSC / Dev Meeting

[Y Song via iovisor-dev]

On Wed, May 2, 2018 at 4:39 PM, Brenden Blanco via iovisor-dev
 wrote:
> Hi All,
>
> Thanks for joining the discussion today. As usual, here are my notes.
>
> -Brenden
>
> === Discussion ===
>
> John:
> - sockmap fixes pushed
>   - fixed broken tests
> - sockmap hash impl next
> - bounded loop rfc making progress
> - cilium code using sockhash almost finished as well
>
> Yonghong:
> - python3 test cleanup
>   - except memleak tool

This is the test_tools_memleak issue I mentioned.
https://github.com/iovisor/bcc/issues/1685

I would be great if somebody who knows python (esp. python3) better
can help take a look.
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[iovisor-dev] minutes: IO Visor TSC / Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for joining the discussion today. As usual, here are my notes.

-Brenden

=== Discussion ===

John:
- sockmap fixes pushed
  - fixed broken tests
- sockmap hash impl next
- bounded loop rfc making progress
- cilium code using sockhash almost finished as well

Yonghong:
- python3 test cleanup
  - except memleak tool
- raw tracepoint support in bcc
  - runqlat tool
  - bio tracing
  - more precise than kprobes
- next work: introspection - bpf trace program in perf

Martin:
- BTF id patch WIP
  - BTF id -> BTF map
- next: support function pointer type in BTF

William:
- moving bpf tunnel example -> selftest
- hitting issue with long running test tunnel cases
  - try enabling kasan to debug
- verifier issue bugfix (ctx + constant arithmetic) WIP

Daniel:
- finalizing removal of some inst from jit
- few bugfixes in x86 jit

Alexei:
- AF_XDP patches being reviewed, looks ok

Jesper:
- Testing AF_XDP patches currently
  - no driver changes needed with xdp_redirect
  - driver changes still needed for zerocopy
  - intel: 12mpps, mlnx: 9mpps drop

Brendan:
- CFP for USENIX LISA in October, Nashville TN

=== Attendees ===
Brenden Blanco
Alex Reece
Jakub Kicinski
Martin Lau
Quentin Monnet
Sandipan
Jiong Wang
William Tu
Alexei Starovoitov
Alexander Duyck
John Fastabend
Jesper Brouer
Daniel Borkmann
Yonghong Song
Brendan Gregg
Ferris
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[iovisor-dev] minutes: IO VIsor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending the meeting today. Here are my notes from the call.

Cheers,
Brenden

=== Status ===

Yonghong
- Debugging incorrect user stack
  - fastpath vs slowpath register difference
  - should be updated in 4.9+ (LTS flavors)
- user stack id - doesn't have full access, trying to improve
- bpf perf event introspection

Daniel
cgroup bind and connect patches merged
- 3 new hooks for container management - used by fb
sockmap ingress support added
raw tracepoint
- use all tp arguments directly from bpf
some prep patches for upcoming features
- btf, few others
clang compiled kernel issue with bpffs
- c lang constant merging flag turned off

Joe
sock lookup progress
- improvements to verifier for tracking reference scope
- next rfc soon

John
Some patches merged, some just missed this window
- next support for lookup by hash
Adding Cilium support for sockmap soon
Rearranging selftests/examples for sockmap

Jakub
adding support for offloading of a few features
- inline map helpers
- atomic add
- some performance improvements
Next window - perf ring output support
Working on 32 bit register support in llvm

Martin
BTF support V2
- pretty print from kernel
- includes pahole converter
next: LLVM directly generate BTF with -g

=== Attendees ===
Dan Siemon
Brenden Blanco
Alex Reece
Alexander Duyck
Daniel Borkmann
Jakub Kicinski
Joe Stringer
Mauricio Vasquez
Yonghong Song
Martin
Quentin Monnet
Tom
George Wilson
Andy Gospodarek
Jiong Wang
Saeed
Francois
Joel
jcanseco
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi all,

Thanks for joining the discussion today, as usual my notes of the discussion
are included below.

Cheers,
Brenden

=== Discussion ===

Alexei
- microkernel/umh work - see lkml

Yonghong
- working on skb segmentation problem
  - ipv4/v6 transition
  - bpf on bpf clsact ingress

Brenden
- bcc release?
  - planning to go with a 1.0 tag soon

Ferris
- rust library for interfacing with bpf
  - more details to be announced in the future

Jesper
- Pushing internally to get bpf support officially enabled (rhel8)
- some progress detected on af_xdp patches

John
- sockmap sendmsg/sendfile merged
- ingress redirect upcoming
- sockmap hashmap lookup support
- fixes for mem charge leak
- reorganize samples into selftests
- documentation work

Brendan
- some minor tools update to use tracepoints
- some tools written again bpftrace

Martin
- CTF patches almost ready, to be posted in a couple weeks


=== Attendees ===
Brenden Blanco
Andy Gospodarek
Daniel Borkmann
Ferris
Logan Blyth
Tom
Alexei
Joe Stringer
Jesper Brouer
Jakub Kicinski
George Wilson
Yonghong Song
Martin Lau
Quentin Monnet
Edwin Peer
Brendan Gregg
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi all,

Thanks for joining the call today! Please see my notes from the
discussion included below.

=== Status ===

Sargun:
seccomp-ebpf - verifier hurdles
- wants synchronous filtering as minimum feature to allow the verifier risk
- current rcu locking approach was nacked
discussion about how bpf punts to userspace daemon
- problems with passing metadata back and forth

Jesper:
xdp redirect memory return api rfc
- patches under review on ml
- some questions about dma mapping in the api
- how to unmap page when device has already gone down?
- or when page pool is full?

Issue: enabling redirect to other device with no xdp rx program running
currently results in silent failure.
- Have an ethtool flag to enable tx devices -> reconfigure queues?

Brendan:
bpftrace - higher level frontend to bcc/bpf
- making good progress
  - 70% feature complete
  - symbol resolution missing
  - dereference of c structs
- depends on ctf?
- test suite exists
  - uses llvm-ir diff against previous builds to sanity check
- packaging?
  - tbd


=== Attendees ===
Brenden Blanco
Quentin Monnet
Tom
Alexander Duyck
Jiong Wang
Sandipan
Sargun Dhillon
Jakub Kicinski
Saeed
Daniel Borkmann
Ferris
Jesper Brouer
Brendan Gregg
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi all,

Thanks for attending the call this week. My notes are included below.

=== Updates ===

DTrace GPLed in Dec 2017
- To help with Oracle Linux port
- Should we take dtrace kernel code into linux?
  - opinion: probably not necessary now, more applicable 5 years ago
- How about dtrace frontend?
  - may have more short term value
  - combine with bpftrace?
  - who would work on it?
  - userspace tools are now UPL - how does that work with apache2?
- CTF
  - currently forking the format into BTF
  - exceed 32k types, other limitations
  - still, is the code useful to combine?

bpfilter announcement
- lots of lwn/reddit/hackernews comments

Brenden:
- Fixes for python3 string encoding
  - please test tools with python3 -W and submit PRs/issues
- todo: push clang ir rewriter to github branch

Yonghong:
- Kernel related bugfixes
  - memory leak in shared lpm map

Daniel:
- bpfilter work
- retpoline work in tail call code of x86 jit
  - also arm64

John:
- some more sockmap changes
  - tx hooks
  - more testing, cleanup
  - optimizations in followup patches

Joe:
- Soliciting feedback for socket sharing patches
  - looking into storing data along with socket
- scratch accessible from bpf program
- How to protect scratch area?
  - new lock helper idea

Sargun:
- Asking for feedback on seccomp ebpf changes
  - desires access to read-only map for
  - use case for scratch buffer primitive as well

Brendan:
- New pcp-bcc-pmda plugin by redhat
  - tbd: integrate into vector

Jesper:
- XDP redirect work
  - bugfixes
  - page free and return API next
- getting help from mellanox devs
- XDP bulk xmit for rx

=== Attendees ===
Brenden Blanco
Eduard Serra
Alexei Starovoitov
Joe String
Jakub Kicinski
Jiong Wang
Mauricio Vasquez
Quentin Monnet
Saeed
Sandipan
Sargun Dhillon
Brendan Gregg
Yonghong Song
Jesper Brouer
Alexander Duyck
Edwin Peer
PJ Waskiewicz
Daniel Borkmann
Nic Viljoen
John Fastabend
Alexander Duyck
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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

On Wed, Feb 21, 2018 at 11:55 AM, Brenden Blanco  wrote:
> Hi all,
>
> Thanks for attending the call this week. My notes are included below.
>
> === Updates ===
>
> DTrace GPLed in Dec 2017
> - To help with Oracle Linux port
> - Should we take dtrace kernel code into linux?
>   - opinion: probably not necessary now, more applicable 5 years ago
> - How about dtrace frontend?
>   - may have more short term value
>   - combine with bpftrace?
>   - who would work on it?
>   - userspace tools are now UPL - how does that work with apache2?
> - CTF
>   - currently forking the format into BTF
>   - exceed 32k types, other limitations
>   - still, is the code useful to combine?
>
> bpfilter announcement
> - lots of lwn/reddit/hackernews comments
>
> Brenden:
> - Fixes for python3 string encoding
>   - please test tools with python3 -W and submit PRs/issues
> - todo: push clang ir rewriter to github branch

As requested, I have pushed the WIP code to
https://github.com/iovisor/bcc/tree/ir-probe-rewrite. Only one of the
two test cases currently works. The basic idea is to use the pointer
alias info to track which loads read from on-stack memory and maps,
and treat the rest as unsafe reads and rewrite them into
bpf_probe_read calls. Map data is not yet handled.

>
> Yonghong:
> - Kernel related bugfixes
>   - memory leak in shared lpm map
>
> Daniel:
> - bpfilter work
> - retpoline work in tail call code of x86 jit
>   - also arm64
>
> John:
> - some more sockmap changes
>   - tx hooks
>   - more testing, cleanup
>   - optimizations in followup patches
>
> Joe:
> - Soliciting feedback for socket sharing patches
>   - looking into storing data along with socket
> - scratch accessible from bpf program
> - How to protect scratch area?
>   - new lock helper idea
>
> Sargun:
> - Asking for feedback on seccomp ebpf changes
>   - desires access to read-only map for
>   - use case for scratch buffer primitive as well
>
> Brendan:
> - New pcp-bcc-pmda plugin by redhat
>   - tbd: integrate into vector
>
> Jesper:
> - XDP redirect work
>   - bugfixes
>   - page free and return API next
> - getting help from mellanox devs
> - XDP bulk xmit for rx
>
> === Attendees ===
> Brenden Blanco
> Eduard Serra
> Alexei Starovoitov
> Joe String
> Jakub Kicinski
> Jiong Wang
> Mauricio Vasquez
> Quentin Monnet
> Saeed
> Sandipan
> Sargun Dhillon
> Brendan Gregg
> Yonghong Song
> Jesper Brouer
> Alexander Duyck
> Edwin Peer
> PJ Waskiewicz
> Daniel Borkmann
> Nic Viljoen
> John Fastabend
> Alexander Duyck
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending today. Below you will find my notes from the call.

Cheers,
Brenden

=== Status ===

Alexei:
- Security updates for BPF
- Patching uses of BPF for speculative execution
  - variant 1, one more patch in progress
  - variant 2, option to toggle off interpreter

Yonghong:
- Fixes for bcc
- kernel fixes for get next key
  - stack map iteration
  - goal: keep consistent with hash map iteration
- issues for usdt, probe name overlap

Brenden:
- Some work on CTF generation

Daniel:
- Working on spectre patches and bugfixes

JohnF:
- sockmap tx hook
  - monitor sendmsg/sendpage
- sample improvements to ease development/debugging/benchmarking

Jesper:
- xdp rx queue merged
  - tracking followup fixes
  - need to extend for memory return api
- todo: cpumap for generic xdp
- add cpumap support into suricata
- xdp_data_meta - want to combine skb->mark+cpumap to fine tune multicore
  handling of packets


=== Attendees ===
Brenden Blanco
Alexander Duyck
Daniel Borkmann
Edwin Peer
Jakub Kicinski
Jesper Brouer
Jiong Wang
Quentin Monnet
Sandipan
Marco Leogrande
Mauricio Vasquez
Nic Viljoen
Andy Gospodarek
Maciej Fijalkowski
Yonghong Song
Rony Efraim
Alexei Starovoitov
Gordon Marler
John Fastabend
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Thanks all for attending today. Below you may find the notes from the call. We
will be skipping the next call and resuming on Jan 10. See you all in the new
year!

=== Status ===
Yonghong:
- bcc: Fixed struct with alignment/int128 quirks
  - match in python
- kernel: query prog array
  - used for event hooks with multiple programs attached
  - debugging use case
- kernel: uprobe speedup patch landed

Jesper:
- submitted

Quentin:
- working on bpf syscall man page / helpers man page
  - where should this work go?
  - A: should go in kernel.org somewhere
 git.kernel.org (this includes kernel, libc, etc.)
if automatically generated, need to occassionally sync from kernel to
  manpage repo
sync once per release
  - contact Michael Kerisk

Jiong:
- Continuing 32bit bpf support in clang
  - support for rotate instruction? more optimal than shift combinations
- benchmark with jhash inlined use cases
  - send experimental patches to yonghong/daniel

Daniel:
- Some ptregs fixes into bpf tree
- Adding development documentation
- Fixes for some jits
- Work continues on bpf qdisc

John:
- Porting sockmap for other use case (ULP layer)
- Reviewing call patches from Alexei

Rony:
- Q: Progress on BPF offload?
  - A: not much discussion yet
  - What does a BPF (offloaded) -> BPF (XDP) interface look like?
- some vendors may accept P4 -> microcode (through firmware api)
  that can as fallback be compiled into BPF
- should we avoid an out of band api for offloading the parsing program
  into silicon?
  - John has tried such APIs in the past, and rejected due to not wanting
to add new api besides bpf+tc

=== Attendees ===
Brenden Blanco
Jakub Kicinski
Jiong Wang
Quentin Monnet
Rony Efraim
Mauricio Vasquez
Andy Gospodarek
Alexei Starovoitov
Yonghong Song
Daniel Borkmann
John Fastabend
Brendan Gregg
Nic Viljoen
Edwin Peer
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending the meeting today, here are my notes.

=== Status ===
Netdev 2.2 next week
- Live streaming available
  - link to be sent out when available

Brenden:
- Increase cadence for updating package version
  - todo: update 0.4.1

Alexei:
- Work proceeds on call between programs
  - bpf loader will start to look like a linker
  - still no loops
  - arbitrary argument definition

JohnF:
- work on sockmap
  - tcp hook
  - multiple cgroups
- bounded for loops
  - rough sketch
  - detect nested loops = reject
  - finding linearly increasing/decreasing loops
- finally, what is the bound of the loop
  - what about counters that are on stack instead of register?

Yonghong:
- fixing arm64 issues
  - netperf missing, other tests passing
- uprobe performance improvements

Martin:
- added small bpf debugging tool to bcc

Kenny:
- TPM from LF
  - Hi!

JohnB:
- Also saying Hi from Netflix

=== Attendees ===
Jakub Kicinski
Kenny Paul
Marco Leogrande
Panagiotis Moustafe
Quentin Monnet
Alexei Starovoitov
Brenden Blanco
John Bennett
Alexander Duyck
Yonghong Song
Prem
Nic Viljoen
John Fastabend
Teng Qin
Kenny Paul
Jesper Brouer
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending the call today. Below are my notes.

=== Status ===

Alexei:
- 1 patch / day
- burdensome on alexei/daniel
  - how to scale?
  - to be discussed at netconf
- working on calls
  - can load relatively large files
  - rfc to come before netdev
  - memory pressure in the verifier
- First TCP tracepoints accepted
  - 5 more coming soon
  - tcp set state has some corner case where it is missed

Daniel:
- fixes for verifier
  - llvm generates some compare/jumps that aren't covered
  - off by 1 in xdp data_end checks
- lpm needs get next key helper for dumping to userspace
- plan to support more drivers for xdp metadata

Brendan:
- LISA in a couple weeks - 2 bpf talks from Sasha, 1 from Brendan

Jakub:
- How to print 2nd phase bpf verifier output from offloaded program?
  - quirk: it runs at attach time, not load time
  - Maybe try a dry run somehow?
  - Intermixing of driver specific errors?
  - Same problem for maps
  - Include offload check at load time instead
  - New system call for "BPF_PROG_PREPARE", in between load and offload
- jit a loaded bpf prog for a specific arch/offload

=== Attendees ===
Marco Leogrande
Brenden Blanco
Alexander Duyck
Daniel Borkmann
Jakub Kicinski
Carlos Neira
Quentin Monnet
Alexei Starovoitov
Jiong
Brendan Gregg
Mauricio Vasquez
Nic Viljoen
Gordon Marler
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi all,

Thanks for attending the call today. Here are my notes. Also, please be advised
that we will be moving to a 30 min time slot going forward.

=== Status ===

Yonghong:
- Added source debugging printer for bcc
  - Requires 6.0 (possible but needs volunteers to backport to 5.0)
- Permit multiple programs to attach to single tracepoint/probe
  - Uses ast's prog array for cgroups style attachment
- Validating arm64 support
  - May help with arm32 support too

Alexei:
- Still working on calling routines (6 months and counting)
  - Big changes in verifier

Jesper:
- cpumap type available with xdp redirect

Daniel:
- Metadata->skb landed
  - Other drivers to come
- Integrating xdp support into cilium

John:
- Fixes for sockmap
  - Adding support for ingress flags

To-do list @ github.com/iovisor/bcc/issues/574 has been updated
- stringmap and bounded loops are important
- network protocol parsing - lots of looping requirements
  - http2, etc.

Panagiotis (elasticcloud)
- Interested in security (networking/sandboxing)
- hitting limitations of seccomp-bpf and no pointer dereferences
  - is aware of landlock, to be looked into
  - should address needs

Andy:
- Close to adding bcm xdp_redirect suppport

=== Attendees ===
Brenden Blanco
Marco Leogrande
Quentin Monnet
Jakub Kicinski
Mauricio Vasquez
Alexander Duyck
Yonghong Song
Alexei Starovoitov
Andy Gospodarek
Panagiotis Moustafellos
Jesper Brouer
Nic Viljoen
Daniel Borkmann
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[iovisor-dev] minutes: IO Visor TSC/Dev meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending the call yesterday, here are my notes:


=== News ===

Linux Plumbers was last week, and included an increasing focus on BPF for
tracing and other use cases over previous years. The tracing/BPF track on Friday
had a very packed agenda, only allowing 10-15 minutes per talk. For full notes
on the discussions, please check out the etherpad at:
https://etherpad.openstack.org/p/LPC2017_Tracing

Other upcoming conferences:
Kernel Recipes - Sept 27-29
https://kernel-recipes.org/en/2017/
Brendan - Performance Analysis with BPF

Netdev 2.2 - Nov 8-10
https://netdevconf.org/2.2/
Last day to submit a talk was yesterday, registration is still open


=== Developer Status ===
Brenden
- Work started on a LLVM Debug Info traverser for BCC
  - Should be able to generate CTF data

Martin
- Investigating CTF converter for use in kernel

Jesper
- new map type - cpu
  - like netdev map
  - redirecting to another cpu
  - example: ddos on first cpu
- queue non-dropped packets to other cpu
- other cpu allocs skb

Martin
- worked on tool to iterate over bpf programs and which maps they are using
  - Nic suggests a similar tool from Jakub to iterate programs
   - https://github.com/Netronome/bpf-tool

Jiong
- Working on 32 bit bpf backend in llvm
  - (makes netronome happy)
- Please let the community know when something is ready and we can help with
  testing :)

=== Attendees ===

Panagiotis Moustafellos
Nic Viljoen
Mauricio Vasquez
Martin Lau
Marco Leogrande
Jiong
Jesper Brouer
Jakub Kicinski
Edwin Peer
Brenden Blanco
Brendan Gregg
Alexander Duyck
Abder
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending the call today. Here are the notes from the meeting.

Netdev 1.2
reminder: paper submissions
 deadline is Sept 20

Linux Plumbers microconference (next week)
If you have volunteered to lead discussion of a topic, Alexei would like to
remind you that we don't want to be power pointed to death. If you have slides,
they should be for fostering discussion, so please bring only a few :)
We believe the session will be 2-5pm on Friday, but couldn't find confirmation
on the website yet.

=== Status updates ===

Jakub:
- created tool for bpf verifier disassembly
  - verifier -> elf
  - to be shared in near future

William:
- conn track RFC: feedback being addressed
- wildcard map - looking at decision tree algorithm
  - some performance evaluation tbd
  - feedback: ok to make some problem space assumptions to simplify
  implementation complexity

Yonghong:
- looking at uprobe performance issues before plumbers
  - vdso, lttng
- kernel tracepoints - only 1 id limitation
  - improvements?
  - bug with fd closing
- pid inside container
  - helper to manage pid

John:
- Fixes for XDP
  - sockmap detach bug for net
- redirect to ingress support for sockmap
- parsing problems with complex protocols
  - fsm helper?

Daniel:
- Ran some statistics on bpf 4.0 -> 4.13 kernel commits
  - 123 patches (if the note-taker heard correctly)
  - 27 unique contributors
  - last 3 releases were busiest and growing
- XDP to skb metadata transfer
  - tests and reviews

Brendan:
-  bpf automation improvements @netflix
  - flamegraphs with oneclick

Misc:
- Landlock talk at security miniconf during plumbers

Alexei:
- focus is on visibility/debug
- wants to resume function call work

=== Attendees ===
Alexei Starovoitov
Andy Gospodarek
Brendan Gregg
Brenden Blanco
Daniel Borkmann
Flavio Crisciani
Fulvio Russo
Jakub Kicinski
John Fastabend
Mauricio Vasquez
Suchakra Sharma
William Tu
Yonghong Song
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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Alexei Starovoitov via iovisor-dev]

On Wed, Aug 23, 2017 at 4:40 PM, Brenden Blanco via iovisor-dev
 wrote:
> Hi All,
>
> Thanks for joining in to the call today. We shared a round of updates, which 
> are
> included in the notes below.
>
> Also please remember that Plumbers is right around the corner! If you have
> signed up to lead discussion of a topic at the Tracing+BPF microconference,
> Alexei would like to have a brief description of what will be discussed so 
> that
> organizers can update the bylines on the schedule. Please send that soon!

the proposals from tracing wiki need to be re-submitted
to show up in official plumbers schedule.
Please do so here:
https://linuxplumbersconf.org/2017/ocw/events/LPC2017/tracks/640
Anything tracing or bpf related is a good topic to discuss.

Thanks!
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for joining in to the call today. We shared a round of updates, which are
included in the notes below.

Also please remember that Plumbers is right around the corner! If you have
signed up to lead discussion of a topic at the Tracing+BPF microconference,
Alexei would like to have a brief description of what will be discussed so that
organizers can update the bylines on the schedule. Please send that soon!



John F:
- currently working on improvements to sockmap
  - api changes merged
  - sockets can now be in multiple maps
  - bug: tracking down warning in socket cleanup

Daniel:
- currently working on misc net-next fixes
- taking XDP measurements for early drop filters
- next: XDP->CB metadata sharing

Brenden:
- working on some lib cleanups
- starting investigation into including compact c types in maps for plumbers
  conf
  - note from Alexei: Martin is also looking at this, we should sync up
- requests to share WIP patches for bpf+pktgen (done)

Yonghong:
- starting investigation into uprobe performance for plumbers
- planning to also give llvm bpf compiler change overview

William:
- feature request: xdp_redirect with support for multi-dev output/multicast
  - response: has been discssed, and the feature makes sense
  - will take the form of a port group/multi-dev-map with kernel doing the
duplication in the backend

Joe:
- working on rebasing bpf tuple space search table prototype
  - hitting gcc issues with container_of + rcu

Attendees:
Zhiting Zhu
Yonghong Song
William Tu
John Fastabend
Joe Stringer
Flavio Crisciani
Dongsu Park
Daniel Borkmann
Brenden Blanco
Alexei Starovoitov
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for joining the meeting today. Here are the notes!

=== Updates ===

Yonghong:
- allow >2 pids attach to same usdt probe - wip
- next: looking at uprobe performance
  - looked into dyninst
  - researched systemtap approach
- c prog compiled into .so
- instrumentation of binary with jmp
  - limited helpers available
- maps?
- stacks?
  - filters in userspace
- sample rate
- malloc size
  - ongoing

John
- xdp redirect merged!
- ongoing: some minor bugfixes
- next: socket redirect

Alastair:
Welcome to the call! He is working on a new tool called bpftrace, which has a
promising starting codebase.
- new tool for tracing, standalone
- check out github.com/ajor/bpftrace

Daniel:
- adjusted map value verifier fixes
- iproute2 fixes

Joe:
- resuming work on ovs/bpf
- looking at integrating cilium connection tracker with ovs-bpf

!!
New feature request:
- add bpf id printing support to bcc

=== Attendees ===
Alastair
Andy Gospodarek
Brendan Gregg
Brenden Blanco
Daniel Borkmann
Genevieve Bastien
Jakub Kicinski
Joe Stringer
John Fastabend
Marco Leogrande
Mauricio Vasquez
Yonghong Song
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Re: [iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Alexei Starovoitov via iovisor-dev]

On Wed, May 17, 2017 at 2:14 PM, Brenden Blanco via iovisor-dev
 wrote:
> Hi All,
>
> Thanks for attending the call today, here are the notes.

thanks a lot for taking and publishing these notes!

> CFP for Linux Plumbers
> Sept 13-15, Los Angeles
> Tracing microconference accepted
>  (Alexei, Brendan, Josef leading topics)
>  http://wiki.linuxplumbersconf.org/2017:tracing
> Last year was successful, looking forward to more topics
>  (tbd: find previous etherpad)

https://etherpad.openstack.org/p/LPC2016_Tracing
a bit terse, but if you were there last year, it's a good memory refresh :)
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for attending the call today, here are the notes.

==

CFP for Linux Plumbers
Sept 13-15, Los Angeles
Tracing microconference accepted
 (Alexei, Brendan, Josef leading topics)
 http://wiki.linuxplumbersconf.org/2017:tracing
Last year was successful, looking forward to more topics
 (tbd: find previous etherpad)

==
BCC has grown, albeit with some maturity/sore spots

We have a well established core group, but probably need to expand our
feedback
to incorporate those that may not be speaking up. Think users of the tools
rather than developers.

How do we get broader user-group feedback besides mailing list/github
issues?

Brendan:
#1 feedback he has heard - simplify syntax, still compared to dtrace
 awareness via conferences, etc.

Alexei:
 internally, writing programs is hard, struggling with verifier
  - working on llvm improvements
 many kernel hackers @fb have hacked up bcc tools for their own use case

Brenden:
 reach larger user group => collectd integration?
  command line users are the smaller subset of our potential audience
 intel snapd
 collectd
 others?

Going forward:
It's a big library, needs shrink/split
 both in terms of memory usage and disk size
 split out clang/llvm
 split out loader
AI: get some proposals into bcc/issues, either in documentation form to
start
 with, or code
 split header files
 split libraries
 start thinking about external tool integration

==
Alexei:
has started thinking about program chaining (generically)

mistake: tail call solved a need, but helper/map model makes it inflexible

prog chaining should be a single native instruction
 (not done until now because "too hard to verify")
now should be possible to introduce and verify cleanly
direct, indirect, and tail call support
 (stack preserving)
3 new bpf instructions
introduce global variables
verifier changes started
llvm support
 (looks like normal c)
configurable stack upper bound of function
loader would need to parse elf file
main() function concept, still callable via tail call

So far, the above is perhaps 10% compelete, so stay tuned.

==
Attendees:
Alexei Starovoitov
Bilal Anwer
Jesper Brouer
Martin Lau
Mauricio Vasquez
Brenden Blanco
Andy Gospodarek
Nic Viljoen
Daniel borkmann
Suchackra Sharma
Brendan Gregg
John Fastabend
Teng Qin
Jakub Kicinski
Marco Leogrande
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi All,

Thanks for joining the meeting this week. Here are some status updates
from various folks.

William:
Discussed issue he is having with the verifier/llvm
 complex program becomes stack limited
 as a workaround, tried using volatile modifier for some stack variables
 but this causes the verifier to hit the 64k simulated instruction
complexity limit
 reason: no heuristics to prune states involving on-stack variables
 suggested workaround: use per-cpu array to hold state

Brenden:
Saw issue with xdp in virtio
warn on once in drivers/pci/msi.c:1261 pci_irq_vector+0xd4/0xe0
will send description to netdev list

ctf (tracing and types) topics:
Suchakra (tracing)
 - started with babeltrace python bindings
 - discussed optional compile-time dependency on libbabeltrace
 - we agreed for now to work on a separate bcc branch for integration testing

Alexei:
 libraries exist as part of pahole (maintained by Arnaldo):
 payhole is tool for analyzing holes in c datastructures
 supports dwarf+ctf
 parser and emitter
 may need to write emitter from scratch due to licensing, but not too hard
 bitfield representation may need some work
 api: extra section at map create time
  ability to dump as well via syscall
 new name to avoid ambiguity with tracing-ctf?

Andy:
 arm64 compiler issues
 inline assembly parser in llvm
 must-have for tracing to get accurate header definitions
 open PR already exists for hacking it in BCC to ifdef out inline
assembly (ugly)
 suggestion to respin patches to arm list to cleanup defines

Sargun:
 new landlock patches a month ago, progress?
 some discussion, seems stalled (unprivileged requirement)
 alternative: seccomp syscall filtering at global level (with eBPF)
  avoids criu problem

Attendees:
William Tu
Teng
Suchakra Sharma
Sargun Dhillon
Michael Schubert
Mauricio Vasquez
Matteo Bertrone
Martin Lau
Marco Leogrande
Lorenzo David
Joe Stringer
Jan-Erik
Jakub Kicinski
Gary Berger
Flavio Crisciani
Ferris
Daniel Borkmann
Brenden Blanco
Brendan Gregg
Andy Gospodarek
Alexei Starvoitov
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

Hi all,

Thanks to those who attended, here are my minutes from the meeting.

= Conferences past and future =

IO Visor Summit
We had this last week, the conference room was packed and we had a few remote
attendees as well. We are working to upload the videos, collect the slides
(please send them to Debra if you haven't already!), and maybe write a blog
post. If you weren't able to attend, look out for an email shortly.

SCaLEx 15x
Linux 4.x Tracing: Performance Analysis with bcc/BPF
https://www.socallinuxexpo.org/scale/15x/presentations/linux-4x-tracing-performance-analysis-bccbpf
Brendan gave this featured talk, with an estimated 200-300 attendees in the
room. Many people were surprised and impressed with the capabilities, which
means that there are still too many people who don't know about BPF yet! Get
out there and give talks if you can.

O'Reilly Velocity - June 19-22 - Santa Clara, CA
Accepted talk by Brendan, and tutorial by Sasha

Netdev 2.1 - April 6-8 - Montreal, CA
CFP is over, several BPF/XDP topics on the agenda
Jesper: Tutorial on how to program BPF

Dockercon - April 17-20 - Austin, TX
Thomas: Cilium - Network and Application Security with BPF and XDP
Brendan: Container Performance Analysis (not BPF specific)

Other (I didn't catch the name) - Denmark
Jesper: how to use bpf for ddos mitigation

= Development =

Brenden:
Working on changing the way bpf maps are stored in the BPFModule and related
classes, with the hope of having different backend implementations based on
feature requirements (persistence, namespaces). The first user of the change
should be the json type generator, followed by the MapTypesVisitor proposal
(bcc #960).

CTF
Discussion kicked off regarding encoding of types. The use of CTF (compact C
type format) has been mentioned before, and still seems to be the way to go.
Alexei will kick off a discussion thread with some kernel folks who supposedly
have some baseline code work off of.

Suchakra:
 Working on something sip (voice protocol) related, details to come soon
 Some ctf (t=trace) work ongoing, depending on Babeltrace 2.0

= Attendees =
Brenden Blanco
Joe Stringer
Marco Leogrande
Suchakra
Brendan Gregg
Alexei Starovoitov
Matteo Bertrone
Mauricio Vasquez
William Tu
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[iovisor-dev] minutes: IO Visor TSC/Dev Meeting

[Brenden Blanco via iovisor-dev]

IO Visor summit coming, please prepare abstracts if you have something
to discuss

=== Conferences ===
netdev conf coming up, talks needed
Jesper - performance workshop
  DDoS topic
idea: reach out to nic vendors who support xdp
 - future xdp direction
idea: dpdk work
idea: specifically, xdp ring to userspace
 john's proposal for sharing pages

FOSDEM 2017
4 different BPF related talks:
 https://fosdem.org/2017/schedule/event/cilium/
 https://fosdem.org/2017/schedule/event/ebpf_xdp/
 https://fosdem.org/2017/schedule/event/stateful_ebpf/
 https://fosdem.org/2017/schedule/event/go_bpf/

linux.conf.au
BPF: Tracing and More
https://linux.conf.au/schedule/presentation/96/

BSidesSF
Linux Monitoring at Scale with eBPF
http://sched.co/9IKj

=== Dev Updates ===
bcc - buildbot/jenkins moved over to GCE
slower but cheaper/on demand

Daniel:
tracepoints for bpf accepted
xdp support (new drivers, new features)
verifier fixes
kallsym work wrapping up
lpm trie features and fixes

Jesper:
documentation work
 goal to enable customers to create own DDoS filters instead of RH coding on
 its own

cgroup work:
netns id helper

William:
hitting max stack size
(check printk strings)
unlikely to increase in kernel

=== Attendees ===
Daniel Borkmann
Eduard Serra
Brenden Blanco
Marco Leogrande
Joe Stringer
Davide Celotto
Mauricio Vasquez
Michael Schubert
William Tu
Jesper Brouer
Brendan Gregg
Sargun Dhillon
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