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From: Paolo Bonzini <pbonzini@redhat.com>
To: Vincent Palatin <vpalatin@chromium.org>
Cc: Yu Ning <yu.ning@linux.intel.com>,
	Eduardo Habkost <ehabkost@redhat.com>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Stefan Weil <sw@weilnetz.de>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH v5 3/4] Plumb the HAXM-based hardware acceleration support
Date: Mon, 9 Jan 2017 14:03:24 +0100	[thread overview]
Message-ID: <459d4c70-aaa7-0d4d-e6c2-5a439243e481@redhat.com> (raw)
In-Reply-To: <CAP_ceTx+SXzZeg1BrF9ibAEm6MvBma+aMseMzLMcrQV_JjeOXg@mail.gmail.com>



On 06/01/2017 15:08, Vincent Palatin wrote:
>>>>> Apart from the above change, can you check if there are some less
>>>>> heavyeight methods to force an exit?  I can think of QueueUserAPC with
>>>>> an empty pfnAPC here, and SleepEx(0, TRUE) in qemu_hax_cpu_thread_fn
>>>>> before qemu_wait_io_event_common.
>>>> Actually I don't know a good test case to verify such a change, any advice ?
>> In fact there is a race anyway:
> Thanks for the detailed examples and thoughts.
> The timing/benchmarking code might actually need some kind of per-vcpu
> time storage, but that's a detail.
> I have experimented with it and so far, I have mainly generated random
> numbers ...
> I have yet to find a use-case where the current code (with
> SuspendThread/ResumeThread) yields a better latency than just nothing
> instead :(

:)  Does QueueUserAPC generate better latency?

Windows delivers the scheduler tick to the first physical CPU.  Try
pinning QEMU away from the first CPU.

Paolo

  reply	other threads:[~2017-01-09 13:03 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-19 16:24 [Qemu-devel] [PATCH v5 0/4] Add HAX support Vincent Palatin
2016-12-19 16:24 ` [Qemu-devel] [PATCH v5 1/4] kvm: move cpu synchronization code Vincent Palatin
2016-12-19 16:24 ` [Qemu-devel] [PATCH v5 2/4] target-i386: Add Intel HAX files Vincent Palatin
2016-12-19 16:24 ` [Qemu-devel] [PATCH v5 3/4] Plumb the HAXM-based hardware acceleration support Vincent Palatin
2016-12-22  9:57   ` Paolo Bonzini
2017-01-05 13:50     ` Vincent Palatin
2017-01-05 14:01       ` Paolo Bonzini
2017-01-05 21:38         ` Paolo Bonzini
2017-01-06 14:08           ` Vincent Palatin
2017-01-09 13:03             ` Paolo Bonzini [this message]
2017-01-09 16:54               ` Vincent Palatin
2017-01-09  6:17           ` Yu Ning
2016-12-19 16:24 ` [Qemu-devel] [PATCH v5 4/4] hax: add Darwin support Vincent Palatin
2016-12-22  9:49   ` Paolo Bonzini
2017-01-05 13:50     ` Vincent Palatin

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