Re: [libvirt] [v6 00/10] Support cache tune in libvirt

Addressed comment from v6 -> v5 Marcelo: * Support other APPs to operate /sys/fs/resctrl at same time Libvirt will scan /sys/fs/resctrl again before doing cache allocation. patch 10 will address this. Addressed comment from v4 -> v5: Marcelo: * Several typos * Use flock instead of virFileLock Addressed comment from v3 -> v4: Daniel & Marcelo: * Added concurrence support Addressed comment from v2 -> v3: Daniel: * Fixed coding style, passed `make check` and `make syntax-check` * Variables renaming and move from header file to c file. * For locking/mutex support, no progress. There are some discussion from mailing list, but I can not find a better way to add locking support without performance impact. I'll explain the process and please help to advice what shoud we do. VM create: 1) Get the cache left value on each bank of the host. This should be shared amount all VMs. 2) Calculate the schemata on the bank based on all created resctrl domain's schemata 3) Calculate the default schemata by scaning all domain's schemata. 4) Flush default schemata to /sys/fs/resctrl/schemata VM destroy: 1) Remove the resctrl domain of that VM 2) Recalculate default schemata 3) Flush default schemata to /sys/fs/resctrl/schemata The key point is that all VMs shares /sys/fs/resctrl/schemata, and when a VM create a resctrl domain, the schemata of that VM depends on the default schemata and all other exsited schematas. So a global mutex is reqired. Before calculate a schemata or update default schemata, libvirt should gain this global mutex. I will try to think more about how to support this gracefully in next patch set. Marcelo: * Added vcpu support for cachetune, this will allow user to define which vcpu using which cache allocation bank. <cachetune id='0' host_id=0 size='3072' unit='KiB' vcpus='0,1'/> vcpus is a cpumap, the vcpu pids will be added to tasks file * Added cdp compatible, user can specify l3 cache even host enable cdp. See patch 8. On a cdp enabled host, specify l3code/l3data by <cachetune id='0' host_id='0' type='l3' size='3072' unit='KiB'/> This will create a schemata like: L3data:0=0xff00;... L3code:0=0xff00;... * Would you please help to test if the functions work. Martin: * Xml test case, I have no time to work on this yet, would you please show me an example, would like to amend it later.

This series patches are for supportting CAT featues, which also called cache tune in libvirt. First to expose cache information which could be tuned in capabilites XML. Then add new domain xml element support to add cacahe bank which will apply on this libvirt domain. This series patches add a util file `resctrl.c/h`, an interface to talk with linux kernel's system fs. There are still one TODO left: 1. Expose a new public interface to get free cache information. 2. Expose a new public interface to set cachetune lively. Some discussion about this feature support can be found from: https://www.redhat.com/archives/libvir-list/2017-January/msg00644.html Eli Qiao (10): Resctrl: Add some utils functions Resctrl: expose cache information to capabilities Resctrl: Add new xml element to support cache tune Resctrl: Add private interface to set cachebanks Qemu: Set cache banks Resctrl: enable l3code/l3data Resctrl: Make sure l3data/l3code are pairs Resctrl: Compatible mode for cdp enabled Resctrl: concurrence support Resctrl: Scan resctrl before doing cache allocation docs/schemas/domaincommon.rng | 46 ++ include/libvirt/virterror.h | 1 + po/POTFILES.in | 1 + src/Makefile.am | 1 + src/conf/capabilities.c | 56 ++ src/conf/capabilities.h | 23 + src/conf/domain_conf.c | 182 +++++++ src/conf/domain_conf.h | 19 + src/libvirt_private.syms | 11 + src/nodeinfo.c | 64 +++ src/nodeinfo.h | 1 + src/qemu/qemu_capabilities.c | 8 + src/qemu/qemu_driver.c | 6 + src/qemu/qemu_process.c | 53 ++ src/util/virerror.c | 1 + src/util/virresctrl.c | 1208 +++++++++++++++++++++++++++++++++++++++++ src/util/virresctrl.h | 88 +++ 17 files changed, 1769 insertions(+) create mode 100644 src/util/virresctrl.c create mode 100644 src/util/virresctrl.h -- 1.9.1