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Date: Wed, 13 Apr 2011 22:16:16 +0200
From: Aurelien Jarno <aurelien@aurel32.net>
Message-ID: <20110413201615.GA15989@volta.aurel32.net>
References: <cover.1302553661.git.jan.kiszka@web.de>
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Subject: Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, Marcelo Tosatti <mtosatti@redhat.com>, qemu-devel@nongnu.org

On Mon, Apr 11, 2011 at 10:27:41PM +0200, Jan Kiszka wrote:
> These patches were posted before. They bring down the overhead of the
> io-thread mode for TCG here, specifically when emulating SMP.
> 
> The major change in this version, besides rebasing, is the exclusion of
> KVM from the main loop polling optimization.
> 
> 
> 
> Jan Kiszka (3):
>   Do not drop global mutex for polled main loop runs
>   Poll main loop after I/O events were received
>   Do not kick vcpus in TCG mode
> 
>  cpus.c   |    2 +-
>  sysemu.h |    2 +-
>  vl.c     |   22 ++++++++++++++++------
>  3 files changed, 18 insertions(+), 8 deletions(-)
> 

Thanks for working on improving the io-thread with TCG. Your patches 
make sense, but they don't seems to fix the slowdown observed when
enabling the io-thread. Well maybe they were not supposed to. This is
for example the results of netperf between guest and host using virtio:

no io-thread            122 MB/s
io-thread                97 MB/s
io-thread + patches      98 MB/s

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net