From: Richard Henderson <rth@twiddle.net>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: qemu-devel <qemu-devel@nongnu.org>,
Anthony Liguori <aliguori@us.ibm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sasha Levin <levinsasha928@gmail.com>, kvm <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [PATCH v2] Register Linux dyntick timer as per-thread signal
Date: Fri, 17 Jun 2011 11:06:49 -0700 [thread overview]
Message-ID: <4DFB97B9.2030205@twiddle.net> (raw)
In-Reply-To: <4DFB1D9D.7060108@siemens.com>
On 06/17/2011 02:25 AM, Jan Kiszka wrote:
> Derived from kvm-tool patch
> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/74309
>
> Ingo Molnar pointed out that sending the timer signal to the whole
> process, just blocking it everywhere, is suboptimal with an increasing
> number of threads. QEMU is also using this pattern so far.
>
> Linux provides a (non-portable) way to restrict the signal to a single
> thread: We can use SIGEV_THREAD_ID unless we are forced to emulate
> signalfd via an additional thread. That case could theoretically be
> optimized as well, but it doesn't look worth bothering.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
r~
WARNING: multiple messages have this Message-ID (diff)
From: Richard Henderson <rth@twiddle.net>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>,
Sasha Levin <levinsasha928@gmail.com>
Subject: Re: [Qemu-devel] [PATCH v2] Register Linux dyntick timer as per-thread signal
Date: Fri, 17 Jun 2011 11:06:49 -0700 [thread overview]
Message-ID: <4DFB97B9.2030205@twiddle.net> (raw)
In-Reply-To: <4DFB1D9D.7060108@siemens.com>
On 06/17/2011 02:25 AM, Jan Kiszka wrote:
> Derived from kvm-tool patch
> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/74309
>
> Ingo Molnar pointed out that sending the timer signal to the whole
> process, just blocking it everywhere, is suboptimal with an increasing
> number of threads. QEMU is also using this pattern so far.
>
> Linux provides a (non-portable) way to restrict the signal to a single
> thread: We can use SIGEV_THREAD_ID unless we are forced to emulate
> signalfd via an additional thread. That case could theoretically be
> optimized as well, but it doesn't look worth bothering.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
r~
next prev parent reply other threads:[~2011-06-17 18:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-16 9:31 [RFC][PATCH] Register Linux dyntick timer as per-thread signal Jan Kiszka
2011-06-16 9:31 ` [Qemu-devel] " Jan Kiszka
2011-06-16 10:26 ` Ingo Molnar
2011-06-16 10:26 ` [Qemu-devel] " Ingo Molnar
2011-06-16 14:39 ` Richard Henderson
2011-06-16 14:39 ` Richard Henderson
2011-06-16 15:24 ` Alexandre Raymond
2011-06-16 15:24 ` Alexandre Raymond
2011-06-17 9:25 ` Jan Kiszka
2011-06-17 9:25 ` Jan Kiszka
2011-06-17 9:25 ` [PATCH v2] " Jan Kiszka
2011-06-17 9:25 ` [Qemu-devel] " Jan Kiszka
2011-06-17 18:06 ` Richard Henderson [this message]
2011-06-17 18:06 ` Richard Henderson
2011-07-23 16:52 ` Anthony Liguori
2011-07-23 16:52 ` [Qemu-devel] " Anthony Liguori
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