From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Anthony Liguori <aliguori@us.ibm.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [Qemu-devel] [patch 1/2] qemu: sem/thread helpers
Date: Tue, 17 Mar 2009 23:07:07 +0000 [thread overview]
Message-ID: <200903172307.08253.paul@codesourcery.com> (raw)
In-Reply-To: <20090317174217.GA10492@amt.cnet>
On Tuesday 17 March 2009, Marcelo Tosatti wrote:
> On Sun, Mar 15, 2009 at 04:15:52PM +0200, Avi Kivity wrote:
> > Marcelo Tosatti wrote:
> >> +
> >> +struct QemuSem {
> >> + sem_t sema;
> >> +};
> >
> > Why aren't you using pthread_mutex_t?
>
> Because we want the thread waiting on the lock to be awakened
> once the holder releases it. This does not happen with pthread
> mutexes AFAIK.
Really? I'd be surprised if there's any difference. The whole point of a mutex
is that it blocks until the other thread releases it. At best it sounds like
you're making fairly sketchy assumptions about the host OS scheduler
heuristics.
Paul
next prev parent reply other threads:[~2009-03-17 23:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-11 16:16 [Qemu-devel] [patch 0/2] RFC: separate thread for IO Marcelo Tosatti
2009-03-11 16:16 ` [Qemu-devel] [patch 1/2] qemu: sem/thread helpers Marcelo Tosatti
2009-03-11 16:33 ` [Qemu-devel] " Anthony Liguori
2009-03-11 16:48 ` [Qemu-devel] " Paul Brook
2009-03-11 16:56 ` Anthony Liguori
2009-03-11 16:58 ` Marcelo Tosatti
2009-03-18 18:47 ` Marcelo Tosatti
2009-03-15 14:15 ` Avi Kivity
2009-03-17 17:42 ` Marcelo Tosatti
2009-03-17 23:07 ` Paul Brook [this message]
2009-03-17 23:43 ` Marcelo Tosatti
2009-03-11 16:16 ` [Qemu-devel] [patch 2/2] qemu: separate thread for io Marcelo Tosatti
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