[Qemu-devel] [PATCH v5 0/5] migration: Dynamic cpu throttling for auto-converge

["Jason J. Herne" <jjherne@linux.vnet.ibm.com>]

This patch set provides a new method for throttling a vcpu and makes use of said
method to dynamically increase cpu throttling during an autoconverge
migration until the migration completes.

This work is related to the following discussion:
https://lists.gnu.org/archive/html/qemu-devel/2015-03/msg00287.html

Previous version review is here:
https://lists.gnu.org/archive/html/qemu-devel/2015-07/msg00734.html

Changelog
-----------
v5
- Add cpu->throttle_thread_scheduled flag to prevent callbacks from stacking up
- Correct error in formula used to reset the timer
- Add atomic operations to protect throttle_percentage
- Make use of cpu_throttle_get_percentage() instead of accessing data directly
- Various small formatting/style fixes
v4
- Switch to a static timer
- Use QEMU_CLOCK_VIRTUAL_RT instead of QEMU_CLOCK_REALTIME
- Get rid of throttle_timer_stop, use throttle_percentage = 0 instead
- Calculate throttle_ratio directly in cpu_throttle_thread
- Consolidate timer mod operations to single function
- Remove some unneeded cpu_throttle_active() checks
- Check for throttle_percentage == 0 in cpu_throttle_thread
- Change throttle_percentage to unsigned int
- Renamed cpu_throttle_timer_pop to cpu_throttle_timer_tick
v3
- Cpu throttling parameters moved from CPUState to global scope
- Throttling interface now uses a percentage instead of ratio
- Migration parameters added to allow tweaking of how aggressive throttling is
- Add throttle active check to the throttle stop routine.
- Remove asserts from throttle start/stop functions and instead force the input
  to fall within the acceptable range
- Rename cpu_throttle_start to cpu_throttle_set to better describe its purpose
- Remove unneeded object casts
- Fixed monitor output formatting
- Comment cleanups
v2
- Add cpu throttle ratio output to hmp/qmp info/query migrate commands
v1
- Initial

Jason J. Herne (5):
  cpu: Provide vcpu throttling interface
  migration: Parameters for auto-converge cpu throttling
  migration: Dynamic cpu throttling for auto-converge
  qmp/hmp: Add throttle ratio to query-migrate and info migrate
  migration: Disambiguate MAX_THROTTLE

 arch_init.c           | 88 ++++++++++++++++++---------------------------------
 cpus.c                | 78 +++++++++++++++++++++++++++++++++++++++++++++
 hmp.c                 | 21 ++++++++++++
 include/qom/cpu.h     | 43 +++++++++++++++++++++++++
 migration/migration.c | 57 +++++++++++++++++++++++++++++++--
 qapi-schema.json      | 40 ++++++++++++++++++++---
 6 files changed, 263 insertions(+), 64 deletions(-)

-- 
1.9.1