Re: [libvirt] [PATCHv5 00/19] Introduce x86 Cache Monitoring Technology (CMT)
> -Original Message- > From: John Ferlan [mailto:jfer...@redhat.com] > Sent: Wednesday, October 10, 2018 12:54 AM > To: Wang, Huaqiang ; libvir-list@redhat.com > Cc: Feng, Shaohe ; Niu, Bing ; > Ding, Jian-feng ; Zang, Rui > Subject: Re: [libvirt] [PATCHv5 00/19] Introduce x86 Cache Monitoring > Technology (CMT) > > > > On 10/9/18 6:30 AM, Wang Huaqiang wrote: > > This series of patches and the series already been merged introduce > > the x86 Cache Monitoring Technology (CMT) to libvirt by interacting > > with kernel resource control (resctrl) interface. CMT is one of the > > Intel(R) x86 CPU feature which belongs to the Resource Director > > Technology (RDT). CMT reports the occupancy of the last level cache, > > which is shared by all CPU cores. > > > > In the v1 series, an original and complete feature for CMT was > > introduced The v2 and v3 patches address the feature for the host > > capability of > CMT. > > v4 is addressing the feature for monitoring VM vcpu thread set cache > > occupancy and reporting it through a virsh command. > > > > We have serval discussion about the enabling of CMT, please refer to > > following links for the RFCs. > > RFCv3 > > https://www.redhat.com/archives/libvir-list/2018-August/msg01213.html > > RFCv2 > > https://www.redhat.com/archives/libvir-list/2018-July/msg00409.html > > https://www.redhat.com/archives/libvir-list/2018-July/msg01241.html > > RFCv1 > > https://www.redhat.com/archives/libvir-list/2018-June/msg00674.html > > > > And the merged commits are list as below, for host capability of CMT. > > 6af8417415508c31f8ce71234b573b4999f35980 > > 8f6887998bf63594ae26e3db18d4d5896c5f2cb4 > > 58fcee6f3a2b7e89c21c1fb4ec21429c31a0c5b8 > > 12093f1feaf8f5023dcd9d65dff111022842183d > > a5d293c18831dcf69ec6195798387fbb70c9f461 > > > > > > 1. About reason why CMT is necessary in libvirt? > > The perf events of 'CMT, MBML, MBMT' have been phased out since Linux > > kernel commit c39a0e2c8850f08249383f2425dbd8dbe4baad69, in libvirt the > > perf based cmt,mbm will not work with the latest linux kernel. These > > patches add CMT feature to libvirt through kernel resctrlfs interface. > > > > 2 Create cache monitoring group (cache monitor). > > > > The main interface for creating monitoring group is through XML > > file. The proposed configuration is like: > > > > > > > > > > > > + > > Duplication of vcpus is odd for a child entry isn't it? It's not in the > > entry... > Seems odd in this example if you think one 'vcpus' is a copy of another. Actually the two 'vcpus' can be assigned with different vcpu setting. Let's introduce some background. >From the perspective of CPU hardware configuration, it has different hardware resource for allocation group and monitor group. And the number of hardware CLOSID, the hardware class of service ID, determines the number of allocation groups could be created. And the number of hardware RMID, and which is hardware resource monitor ID, determines the monitor groups could be created simultaneously in host. Normally we have more RMIDs and CLOSIDs, that is, we can create more allocations than monitors. Based on this hardware design, kernel introduces the resctrl file system and which has the capability to create more monitors than allocations, and create more than one monitors for each allocation. Allocations can only be created under root directory of '/sys/fs/resctrl' with one exception that the root directory itself is also an allocation, which is called default allocation. For monitors, could be created under default allocation's 'mon_groups' directory, which is directory '/sys/fs/resctrl/mon_groups', or be created under other allocation's 'mon_groups' directory, for example '/sys/fs/resctrl/p0/mon_groups' for allocation 'p0'. Each directory under the allocation's 'mon_group' occupies one RMID, and you can create several directories under this directory. Each allocation itself occupies one RMID and creates a monitor monitoring the cache or memory bandwidth utilization for all CPUs using this RMID. With the help of kernel scheduler, the hardware RMID is assigned to the CPU servicing current Linux thread at time of CPU context switch. That is the RMID could be tracked through PID of vcpu. Here, since both and have the same 'vcpus' attribute but it may pointer to different vcpu list. The rules are: 1. In each entry more than one monitors could be specified. 2. In each entry up to one allocation could be specified. 3. The allocation is using the vcpu list specified in attribute 'vcpus'. 4. A monitor has the same vcpu list as allocatio
Re: [libvirt] [PATCHv5 00/19] Introduce x86 Cache Monitoring Technology (CMT)
On 10/9/18 6:30 AM, Wang Huaqiang wrote: > This series of patches and the series already been merged introduce > the x86 Cache Monitoring Technology (CMT) to libvirt by interacting > with kernel resource control (resctrl) interface. CMT is one of the > Intel(R) x86 CPU feature which belongs to the Resource Director > Technology (RDT). CMT reports the occupancy of the last level cache, > which is shared by all CPU cores. > > In the v1 series, an original and complete feature for CMT was introduced > The v2 and v3 patches address the feature for the host capability of CMT. > v4 is addressing the feature for monitoring VM vcpu thread set cache > occupancy and reporting it through a virsh command. > > We have serval discussion about the enabling of CMT, please refer to > following links for the RFCs. > RFCv3 > https://www.redhat.com/archives/libvir-list/2018-August/msg01213.html > RFCv2 > https://www.redhat.com/archives/libvir-list/2018-July/msg00409.html > https://www.redhat.com/archives/libvir-list/2018-July/msg01241.html > RFCv1 > https://www.redhat.com/archives/libvir-list/2018-June/msg00674.html > > And the merged commits are list as below, for host capability of CMT. > 6af8417415508c31f8ce71234b573b4999f35980 > 8f6887998bf63594ae26e3db18d4d5896c5f2cb4 > 58fcee6f3a2b7e89c21c1fb4ec21429c31a0c5b8 > 12093f1feaf8f5023dcd9d65dff111022842183d > a5d293c18831dcf69ec6195798387fbb70c9f461 > > > 1. About reason why CMT is necessary in libvirt? > The perf events of 'CMT, MBML, MBMT' have been phased out since Linux > kernel commit c39a0e2c8850f08249383f2425dbd8dbe4baad69, in libvirt > the perf based cmt,mbm will not work with the latest linux kernel. These > patches add CMT feature to libvirt through kernel resctrlfs interface. > > 2 Create cache monitoring group (cache monitor). > > The main interface for creating monitoring group is through XML file. The > proposed configuration is like: > > > > > > + Duplication of vcpus is odd for a child entry isn't it? It's not in the entry... > > > + ... but perhaps that means using 4-6 is OK because it's a subset of the parent cachetune 4-7? I'm not sure I can keep track of all the discussions we've had about this, so this could be something we've already covered, but has moved out of my short term memory. > > > > In above XML, created 2 cache resctrl allocation groups and 2 resctrl > monitoring groups. > The changes of cache monitor will be effective in next booting of VM. > > 2 Show CMT result through command 'domstats' > > Adding the interface in qemu to report this information for resource > monitor group through command 'virsh domstats --cpu-total'. > Below is a typical output: > > # virsh domstats 1 --cpu-total > Domain: 'ubuntu16.04-base' > ... >cpu.cache.monitor.count=2 >cpu.cache.0.name=vcpus_1 >cpu.cache.0.vcpus=1 >cpu.cache.0.bank.count=2 >cpu.cache.0.bank.0.id=0 >cpu.cache.0.bank.0.bytes=4505600 >cpu.cache.0.bank.1.id=1 >cpu.cache.0.bank.1.bytes=5586944 >cpu.cache.1.name=vcpus_4-6 So perhaps "this" is more correct 4-6 (I assume this comes from the entryu... >cpu.cache.1.vcpus=4,5,6 Interesting that a name can be 4-6, but these are each called out. Can someone have "5,7,9"? How does that look on the name line and then on the vcpus line. >cpu.cache.1.bank.count=2 >cpu.cache.1.bank.0.id=0 >cpu.cache.1.bank.0.bytes=17571840 >cpu.cache.1.bank.1.id=1 >cpu.cache.1.bank.1.bytes=29106176 Obviously a different example than above with only 1 entry... and the .bytes values for everything doesn't match up with the kb values above. > > > Changes in v5: > - qemu: Setting up vcpu and adding pids to resctrl monitor groups during > re-connection. > - Add the document for domain configuration related to resctrl monitor. > Probably should have posted a reply to your v4 series to indicate you were working on a v5 due to whatever reason so that no one started reviewing it... It takes a "long time" to set aside the time to review large series... Also, while it may pass your compiler, the patch18 needed: -unsigned int nmonitors = NULL; +unsigned int nmonitors = 0; Something I thought I had pointed out in much earlier reviews... I'll work through the series over the next day or so with any luck... It is on my short term radar at least. John > Changes in v4: > v4 is addressing the feature for monitoring VM vcpu > thread set cache occupancy and reporting it through a > virsh command. > - Introduced resctrl default allocation > - Introduced resctrl monitor and default monitor > > Changes in v3: > - Addressed John Ferlan's review. > - Typo fixed. > - Removed VIR_ENUM_DECL(virMonitor); > > Changes in v2: > - Introduced MBM capability. > - Capability layout changed > * Moved from cahe to > * Renamed to >
[libvirt] [PATCHv5 00/19] Introduce x86 Cache Monitoring Technology (CMT)
This series of patches and the series already been merged introduce the x86 Cache Monitoring Technology (CMT) to libvirt by interacting with kernel resource control (resctrl) interface. CMT is one of the Intel(R) x86 CPU feature which belongs to the Resource Director Technology (RDT). CMT reports the occupancy of the last level cache, which is shared by all CPU cores. In the v1 series, an original and complete feature for CMT was introduced The v2 and v3 patches address the feature for the host capability of CMT. v4 is addressing the feature for monitoring VM vcpu thread set cache occupancy and reporting it through a virsh command. We have serval discussion about the enabling of CMT, please refer to following links for the RFCs. RFCv3 https://www.redhat.com/archives/libvir-list/2018-August/msg01213.html RFCv2 https://www.redhat.com/archives/libvir-list/2018-July/msg00409.html https://www.redhat.com/archives/libvir-list/2018-July/msg01241.html RFCv1 https://www.redhat.com/archives/libvir-list/2018-June/msg00674.html And the merged commits are list as below, for host capability of CMT. 6af8417415508c31f8ce71234b573b4999f35980 8f6887998bf63594ae26e3db18d4d5896c5f2cb4 58fcee6f3a2b7e89c21c1fb4ec21429c31a0c5b8 12093f1feaf8f5023dcd9d65dff111022842183d a5d293c18831dcf69ec6195798387fbb70c9f461 1. About reason why CMT is necessary in libvirt? The perf events of 'CMT, MBML, MBMT' have been phased out since Linux kernel commit c39a0e2c8850f08249383f2425dbd8dbe4baad69, in libvirt the perf based cmt,mbm will not work with the latest linux kernel. These patches add CMT feature to libvirt through kernel resctrlfs interface. 2 Create cache monitoring group (cache monitor). The main interface for creating monitoring group is through XML file. The proposed configuration is like: + + In above XML, created 2 cache resctrl allocation groups and 2 resctrl monitoring groups. The changes of cache monitor will be effective in next booting of VM. 2 Show CMT result through command 'domstats' Adding the interface in qemu to report this information for resource monitor group through command 'virsh domstats --cpu-total'. Below is a typical output: # virsh domstats 1 --cpu-total Domain: 'ubuntu16.04-base' ... cpu.cache.monitor.count=2 cpu.cache.0.name=vcpus_1 cpu.cache.0.vcpus=1 cpu.cache.0.bank.count=2 cpu.cache.0.bank.0.id=0 cpu.cache.0.bank.0.bytes=4505600 cpu.cache.0.bank.1.id=1 cpu.cache.0.bank.1.bytes=5586944 cpu.cache.1.name=vcpus_4-6 cpu.cache.1.vcpus=4,5,6 cpu.cache.1.bank.count=2 cpu.cache.1.bank.0.id=0 cpu.cache.1.bank.0.bytes=17571840 cpu.cache.1.bank.1.id=1 cpu.cache.1.bank.1.bytes=29106176 Changes in v5: - qemu: Setting up vcpu and adding pids to resctrl monitor groups during re-connection. - Add the document for domain configuration related to resctrl monitor. Changes in v4: v4 is addressing the feature for monitoring VM vcpu thread set cache occupancy and reporting it through a virsh command. - Introduced resctrl default allocation - Introduced resctrl monitor and default monitor Changes in v3: - Addressed John Ferlan's review. - Typo fixed. - Removed VIR_ENUM_DECL(virMonitor); Changes in v2: - Introduced MBM capability. - Capability layout changed * Moved from cahe to * Renamed to - Document for 'reuseThreshold' changed. - Introduced API virResctrlInfoGetMonitorPrefix - Added more tests, covering standalone CMT, fake new feature. - Creating CMT resource control group will be subsequent job. Wang Huaqiang (19): docs: Refactor schemas to support default allocation util: Introduce resctrl monitor for CMT util: Refactor code for adding PID to the resource group util: Add interface for adding PID to monitor util: Refactor code for determining allocation path util: Add monitor interface to determine path util: Refactor code for creating resctrl group util: Add interface for creating monitor group util: Add more interfaces for resctrl monitor util: Introduce default monitor conf: Refactor code for matching existing resctrls conf: Refactor virDomainResctrlAppend conf: Add resctrl monitor configuration Util: Add function for checking if monitor is running qemu: enable resctrl monitor in qemu conf: Add a 'id' to virDomainResctrlDef qemu: refactor qemuDomainGetStatsCpu qemu: Report cache occupancy (CMT) with domstats qemu: Setting up vcpu and adding pids to resctrl monitor groups during reconnection docs/formatdomain.html.in | 30 +- docs/schemas/domaincommon.rng | 14 +- src/conf/domain_conf.c | 327 ++-- src/conf/domain_conf.h | 12 + src/libvirt-domain.c | 9 + src/libvirt_private.syms
