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Date: Mon, 01 Dec 2014 08:05:17 +0100
From: Peter Lieven <pl@kamp.de>
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Subject: Re: [Qemu-devel] [PATCH 0/7] coroutine: optimizations
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To: Ming Lei <ming.lei@canonical.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>

On 01.12.2014 06:55, Ming Lei wrote:
> On Fri, Nov 28, 2014 at 10:12 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>> As discussed in the other thread, this brings speedups from
>> dropping the coroutine mutex (which serializes multiple iothreads,
>> too) and using ELF thread-local storage.
>>
>> The speedup in perf/cost is about 30% (190->145).  Windows port tested
>> with tests/test-coroutine.exe under Wine.
> The data is very nice, and in my laptop, 'perf cost' can be decreased
> from 244ns to 174ns.
>
> BTW, the cost by using coroutine to run function isn't only from these
> helpers(*_yield, *_enter, *_create, and perf-cost just measures
> this part of cost), but also some implicit/invisible part. I have some
> test cases which can show the problem. If someone is interested,
> I can post them in list.

Of course, maybe the problem can be solved or impaired.

Peter