[PATCH v24 0/8] support dirty restraint on vCPU

huangy81@chinatelecom.cn posted 8 patches 1 year, 10 months ago
There is a newer version of this series
accel/kvm/kvm-all.c             |  46 ++-
accel/stubs/kvm-stub.c          |   6 +
cpus-common.c                   |   8 +
hmp-commands-info.hx            |  13 +
hmp-commands.hx                 |  32 +++
include/exec/cpu-common.h       |   1 +
include/exec/memory.h           |   5 +-
include/hw/core/cpu.h           |   6 +
include/monitor/hmp.h           |   3 +
include/sysemu/dirtylimit.h     |  37 +++
include/sysemu/dirtyrate.h      |  28 ++
include/sysemu/kvm.h            |   2 +
migration/dirtyrate.c           | 227 +++++++++------
migration/dirtyrate.h           |   7 +-
qapi/migration.json             |  80 ++++++
softmmu/dirtylimit.c            | 601 ++++++++++++++++++++++++++++++++++++++++
softmmu/meson.build             |   1 +
softmmu/trace-events            |   7 +
tests/qtest/migration-helpers.c |  22 ++
tests/qtest/migration-helpers.h |   2 +
tests/qtest/migration-test.c    | 255 +++++++++++++++++
tests/qtest/qmp-cmd-test.c      |   2 +
22 files changed, 1292 insertions(+), 99 deletions(-)
create mode 100644 include/sysemu/dirtylimit.h
create mode 100644 include/sysemu/dirtyrate.h
create mode 100644 softmmu/dirtylimit.c
[PATCH v24 0/8] support dirty restraint on vCPU
Posted by huangy81@chinatelecom.cn 1 year, 10 months ago
From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>

v24:
- add "Acked-by: Peter Xu <peterx@redhat.com>" tag in (PATCH [8/8])

v23:

This is v23 of dirtylimit series. Since v22 posted abount 1 month ago,
i did some modifications to make sure it's ready to be queued:

- rebased the master and changed the qapi version tag from 7.0 to 7.1
- do not set error if when query_vcpu_dirty_limit find dirtylimit not
  in service, returning NULL is sufficient. (PATCH v22 [7/8]). 

The following is the history of the patchset, since v22 kind of different from
the original version, i made abstracts of changelog:

RFC and v1: https://lore.kernel.org/qemu-devel/cover.1637214721.git.huangy81@chinatelecom.cn/
v2: https://lore.kernel.org/qemu-devel/cover.1637256224.git.huangy81@chinatelecom.cn/
v1->v2 changelog: 
- rename some function and variables. refactor the original algo of dirtylimit. Thanks for
  the comments given by Juan Quintela.
v3: https://lore.kernel.org/qemu-devel/cover.1637403404.git.huangy81@chinatelecom.cn/
v4: https://lore.kernel.org/qemu-devel/cover.1637653303.git.huangy81@chinatelecom.cn/
v5: https://lore.kernel.org/qemu-devel/cover.1637759139.git.huangy81@chinatelecom.cn/
v6: https://lore.kernel.org/qemu-devel/cover.1637856472.git.huangy81@chinatelecom.cn/
v7: https://lore.kernel.org/qemu-devel/cover.1638202004.git.huangy81@chinatelecom.cn/
v2->v7 changelog:
- refactor the docs, annotation and fix bugs of the original algo of dirtylimit.
  Thanks for the review given by Markus Armbruster. 
v8: https://lore.kernel.org/qemu-devel/cover.1638463260.git.huangy81@chinatelecom.cn/
v9: https://lore.kernel.org/qemu-devel/cover.1638495274.git.huangy81@chinatelecom.cn/
v10: https://lore.kernel.org/qemu-devel/cover.1639479557.git.huangy81@chinatelecom.cn/
v7->v10 changelog:
- introduce a simpler but more efficient algo of dirtylimit inspired by Peter Xu.
- keep polishing the annotation suggested by Markus Armbruster.
v11: https://lore.kernel.org/qemu-devel/cover.1641315745.git.huangy81@chinatelecom.cn/
v12: https://lore.kernel.org/qemu-devel/cover.1642774952.git.huangy81@chinatelecom.cn/
v13: https://lore.kernel.org/qemu-devel/cover.1644506963.git.huangy81@chinatelecom.cn/
v10->v13 changelog:
- handle the hotplug/unplug scenario.
- refactor the new algo, split the commit and make the code more clean.
v14: https://lore.kernel.org/qemu-devel/cover.1644509582.git.huangy81@chinatelecom.cn/
v13->v14 changelog:
- sent by accident.
v15: https://lore.kernel.org/qemu-devel/cover.1644976045.git.huangy81@chinatelecom.cn/ 
v16: https://lore.kernel.org/qemu-devel/cover.1645067452.git.huangy81@chinatelecom.cn/ 
v17: https://lore.kernel.org/qemu-devel/cover.1646243252.git.huangy81@chinatelecom.cn/
v14->v17 changelog: 
- do some code clean and fix test bug reported by Dr. David Alan Gilbert.
v18: https://lore.kernel.org/qemu-devel/cover.1646247968.git.huangy81@chinatelecom.cn/
v19: https://lore.kernel.org/qemu-devel/cover.1647390160.git.huangy81@chinatelecom.cn/
v20: https://lore.kernel.org/qemu-devel/cover.1647396907.git.huangy81@chinatelecom.cn/
v21: https://lore.kernel.org/qemu-devel/cover.1647435820.git.huangy81@chinatelecom.cn/
v17->v21 changelog:
- add qtest, fix bug and do code clean. 
v21->v22 changelog:
- move the vcpu dirty limit test into migration-test and do some modification suggested
  by Peter.

Please review.

Yong.

Abstract
========

This patchset introduce a mechanism to impose dirty restraint
on vCPU, aiming to keep the vCPU running in a certain dirtyrate
given by user. dirty restraint on vCPU maybe an alternative
method to implement convergence logic for live migration,
which could improve guest memory performance during migration
compared with traditional method in theory.

For the current live migration implementation, the convergence
logic throttles all vCPUs of the VM, which has some side effects.
-'read processes' on vCPU will be unnecessarily penalized
- throttle increase percentage step by step, which seems
  struggling to find the optimal throttle percentage when
  dirtyrate is high.
- hard to predict the remaining time of migration if the
  throttling percentage reachs 99%

to a certain extent, the dirty restraint machnism can fix these
effects by throttling at vCPU granularity during migration.

the implementation is rather straightforward, we calculate
vCPU dirtyrate via the Dirty Ring mechanism periodically
as the commit 0e21bf246 "implement dirty-ring dirtyrate calculation"
does, for vCPU that be specified to impose dirty restraint,
we throttle it periodically as the auto-converge does, once after
throttling, we compare the quota dirtyrate with current dirtyrate,
if current dirtyrate is not under the quota, increase the throttling
percentage until current dirtyrate is under the quota.

this patchset is the basis of implmenting a new auto-converge method
for live migration, we introduce two qmp commands for impose/cancel
the dirty restraint on specified vCPU, so it also can be an independent
api to supply the upper app such as libvirt, which can use it to
implement the convergence logic during live migration, supplemented
with the qmp 'calc-dirty-rate' command or whatever.

we post this patchset for RFC and any corrections and suggetions about
the implementation, api, throttleing algorithm or whatever are very
appreciated!

Please review, thanks !

Best Regards !

Hyman Huang (8):
  accel/kvm/kvm-all: Refactor per-vcpu dirty ring reaping
  cpus: Introduce cpu_list_generation_id
  migration/dirtyrate: Refactor dirty page rate calculation
  softmmu/dirtylimit: Implement vCPU dirtyrate calculation periodically
  accel/kvm/kvm-all: Introduce kvm_dirty_ring_size function
  softmmu/dirtylimit: Implement virtual CPU throttle
  softmmu/dirtylimit: Implement dirty page rate limit
  tests: Add dirty page rate limit test

 accel/kvm/kvm-all.c             |  46 ++-
 accel/stubs/kvm-stub.c          |   6 +
 cpus-common.c                   |   8 +
 hmp-commands-info.hx            |  13 +
 hmp-commands.hx                 |  32 +++
 include/exec/cpu-common.h       |   1 +
 include/exec/memory.h           |   5 +-
 include/hw/core/cpu.h           |   6 +
 include/monitor/hmp.h           |   3 +
 include/sysemu/dirtylimit.h     |  37 +++
 include/sysemu/dirtyrate.h      |  28 ++
 include/sysemu/kvm.h            |   2 +
 migration/dirtyrate.c           | 227 +++++++++------
 migration/dirtyrate.h           |   7 +-
 qapi/migration.json             |  80 ++++++
 softmmu/dirtylimit.c            | 601 ++++++++++++++++++++++++++++++++++++++++
 softmmu/meson.build             |   1 +
 softmmu/trace-events            |   7 +
 tests/qtest/migration-helpers.c |  22 ++
 tests/qtest/migration-helpers.h |   2 +
 tests/qtest/migration-test.c    | 255 +++++++++++++++++
 tests/qtest/qmp-cmd-test.c      |   2 +
 22 files changed, 1292 insertions(+), 99 deletions(-)
 create mode 100644 include/sysemu/dirtylimit.h
 create mode 100644 include/sysemu/dirtyrate.h
 create mode 100644 softmmu/dirtylimit.c

-- 
1.8.3.1