[Qemu-devel] [RFC 0/5] Throttle group cooperative round robin scheduling

[Benoît Canet]

Hi,

Here is my current wip on the throttle group support.

For the user interface I implemented Stefanha's idea proposed in Stuttgart.

For the throttling algorithm I use a cooperative round robin scheduler.

Classical round robin works with a fixed HZ ticks and it's totaly incompatible
with the throttling algorithm.

So the cooperative round robin scheduler is a way for each block device to 
decide
if a pause must be done and a timer be armed and most important of all which
other block device of the group must resume the work once the timer is fired.

The advantages of this algorigthm are:

-only one timer active at a given time (no more cpu usage than regular 
throttling)
-no central place didacting the sheduling policy like a didactureship:
 we love collaboration isn't it ?:)
-No need to deal with  incoming queues to collect requests before scheduling 
 then with and dispatchs queues
-Compatible with the throttling code with almost no changes
-As you go scheduling

Best regards

Benoît

Benoît Canet (5):
  throttle: Extract timers from ThrottleState into a separate
    ThrottleTimers structure
  throttle: Add throttle group infrastructure.
  throttle: Add throttle group infrastructure tests
  throttle: Prepare to have multiple timers for one ThrottleState
  throttle: Add throttle group support.

 block.c                        | 173 +++++++++++++++++++++++++++++++-----
 block/qapi.c                   |   2 +-
 blockdev.c                     |  16 +++-
 hmp.c                          |   4 +-
 include/block/block.h          |   2 +-
 include/block/block_int.h      |   9 +-
 include/qemu/throttle-groups.h |  43 +++++++++
 include/qemu/throttle.h        |  42 ++++++---
 qapi/block-core.json           |   5 +-
 qemu-options.hx                |   1 +
 qmp-commands.hx                |   3 +-
 tests/test-throttle.c          | 133 ++++++++++++++++++++--------
 util/Makefile.objs             |   1 +
 util/throttle-groups.c         | 195 +++++++++++++++++++++++++++++++++++++++++
 util/throttle.c                | 103 +++++++++++++++-------
 15 files changed, 616 insertions(+), 116 deletions(-)
 create mode 100644 include/qemu/throttle-groups.h
 create mode 100644 util/throttle-groups.c

-- 
2.1.0.rc1