[Qemu-devel] [PATCH 0/2] coroutine: dynamically scale pool size

[Stefan Hajnoczi <stefanha@redhat.com>]

The coroutine pool reuses exited coroutines to make qemu_coroutine_create()
cheap.  The size of the pool is capped to prevent it from hogging memory after
a period of high coroutine activity.  Previously the max size was hardcoded to
64 but this doesn't scale with guest size.

A guest with lots of disks can do more parallel I/O and therefore requires a
larger coroutine pool size.  This series tries to solve the problem by scaling
pool size according to the number of drives.

Ming: Please let me know if this eliminates the rt_sigprocmask system calls you
are seeing.  It should solve part of the performance regression you have seen
in qemu.git/master virtio-blk dataplane.

Stefan Hajnoczi (2):
  coroutine: make pool size dynamic
  block: bump coroutine pool size for drives

 block.c                   |  4 ++++
 include/block/coroutine.h | 11 +++++++++++
 qemu-coroutine.c          | 25 +++++++++++++++++++------
 3 files changed, 34 insertions(+), 6 deletions(-)

-- 
1.9.3