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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Alex Züpke" <alexander.zuepke@hs-rm.de>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?
Date: Fri, 19 Jun 2015 18:57:46 +0200	[thread overview]
Message-ID: <55844A0A.2070401@redhat.com> (raw)
In-Reply-To: <557B0B21.2030009@hs-rm.de>



On 12/06/2015 18:38, Alex Züpke wrote:
>   CPU #0                       CPU #1
>   ======                       ======
>   ... other stuff ...          WFI (wait for interrupt, like x86 "HLT")
>   send SGI in MPCore
>   polls for completeness
>                  <time passes ...>
>   polls ...
>                  <... and passes ...>
>   still polls ...
>                  <... and passes ...>
>   still polls ...
>                  <... and passes ...>

Shouldn't CPU#0 do a WFE here?  That would work too.

Considering that sooner or later we'll have true multithreaded
emulation, putting a hack doesn't sound like a great prospect.

Paolo

  parent reply	other threads:[~2015-06-19 16:57 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-12 16:38 [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency? Alex Züpke
2015-06-12 18:03 ` Peter Maydell
2015-06-15 14:44   ` Alex Züpke
2015-06-15 14:51     ` Peter Maydell
2015-06-15 15:05       ` Alex Züpke
2015-06-15 18:41         ` Peter Maydell
2015-06-15 18:58         ` Peter Maydell
2015-06-15 20:03           ` Alex Zuepke
2015-06-16 10:33             ` Peter Maydell
2015-06-16 10:59               ` Peter Maydell
2015-06-16 11:11                 ` Alex Züpke
2015-06-16 11:53                   ` Peter Maydell
2015-06-16 12:21                     ` Alex Züpke
2015-06-19 15:53                     ` Peter Maydell
2015-06-23  7:31                       ` Frederic Konrad
2015-06-23  8:09                         ` Peter Maydell
2015-06-23  8:33                           ` Frederic Konrad
2015-06-23 18:15                         ` Peter Maydell
2015-06-25 17:13                           ` Peter Maydell
2015-06-15 15:04 ` Peter Maydell
2015-06-15 15:07   ` Alex Züpke
2015-06-15 15:18     ` Peter Maydell
2015-06-15 15:36       ` Alex Züpke
2015-06-15 15:49         ` Peter Maydell
2015-06-15 16:12           ` Alex Züpke
2015-06-15 21:39           ` Peter Crosthwaite
2015-06-19 16:57 ` Paolo Bonzini [this message]
2015-06-19 17:25   ` Peter Maydell

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