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[Qemu-devel] [PATCH 0/3] Release SMP restriction on Windows host

From: Fabien Chouteau
Subject: [Qemu-devel] [PATCH 0/3] Release SMP restriction on Windows host
Date: Tue, 9 Apr 2013 18:06:52 +0200

As I already explained to this mailling list, we (AdaCore) use QEMU to run a
lot of short executable (~2 secs) on many different targets. In that
configuration the SMP restriction on Windows (QEMU runs only on 1 core) was not
efficient on our 16 cores servers.

Few months ago I asked on this mailing list if the restriction could be
removed. There was no clear answer because nobody was able to tell if it would
work. We decided to give it a try.

During the last months we only found one problem, it was a dead lock between
the TCG and IO thread, this is fixed by the second patch.

We also found that suspendThread() and resumeThread() were not synchronous on
SMP systems, so we added a busy loop to wait for effective suspension.

Since then, we run thousands of QEMU on our SMP Windows servers each day
without any problem. And of course we greatly improve the execution time of our

Fabien Chouteau (1):
  Release SMP restriction on Windows

Olivier Hainque (2):
  Check effective suspension of TCG thread
  Ensure good ordering of memory instruction in cpu_exec

 cpu-exec.c |    8 ++++++++
 cpus.c     |   24 ++++++++++++++++++++++--
 os-win32.c |   18 ------------------
 3 files changed, 30 insertions(+), 20 deletions(-)


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