Hi all, Thanks for attending the meeting today. Below you will find my notes from the call. Hear you all in two weeks!
================================================ Brenden: Overview of conferences over previous month 2 OpenStack presentations from PG and Huawei https://www.youtube.com/watch?v=s-8BSTzD91s https://www.youtube.com/watch?v=1oAsRzrwAAw Linux Plumbers - half day track on tracing No notes/video to share, but see netdev mailer and possibly upcoming lwn.net article. Good progress made on LSM/cgroup hooks, as well as some discussion on userspace tracing Open vSwitch Conference Slides available here: http://www.openvswitch.org/support/ovscon2016/ Daniel: WIP: XDP bug in mlx4/mlx5 ref counting Also WIP: hashing of bpf programs for visibility Soon: bpf in kallsyms (address/name/sha) Adding bpf() tracepoint Alexei: Userspace tracing/live patching for bpf? discussions currently in private, to share soon LRU maps (for LB use case) under review multiple modes - regular/no common cgroups work ongoing - patches soon discussion: improving debuggability add pseudo instruction for "comment" Joe: libbpf work - pinning support ovs con (see above link for slides) William Tu: presented bpf dataplane performance issues due to: p4->bcc->bpf script inefficiencies 1 map lookup per action Alban: Had 4 topics from IRC (3 were discussed): 1. Golang libraries for kprobe-eBPF and perf-maps We agreed to fork the code in github.com/iovisor/iomodules into its own go library. AI: Brenden to send proposal for name of new repo 2. dependencies on kernel headers for kprobe-eBPF There has been some previous discussion of this in github.com/iovisor/bcc/issues/421, but no substantial progress yet. Another alternative that Brenden proposed was to let the API accept LLVM-IR as the input of a BPF() object, such that frontends could "compile" against the headers offline. 3. API stability for a limited set of kprobe-eBPF programs We didn't discuss this, Alban would you like to give us some more context? 4. size of bcc.so when included in (and used from within) a container image wanting to build libbcc against alpine go bindings No work has been done to compile bcc using alpine base. This would be a nice to have if someone out there has some experience or free time. Sargun: While investigating how to implement IPVS-like functionality in BPF, came across the 32-prog tail call limit, wondering how to work around that? Can the limit be enforced with a sysctl? A: no, probably not Instead, we proposed that a map/helper-based approach for capturing the use case, or a new datastructure, would be a better path forward. Sargun may investigate. ================================================ Attendees: Brenden Blanco Alessandro Alban Crequy Marco Leogrande Matteo Daniel Borkmann iaguis Joe Stringer Alexei Sargun
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