From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:49903) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QXdRY-000693-Vs for qemu-devel@nongnu.org; Fri, 17 Jun 2011 14:06:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QXdRX-0006W2-JW for qemu-devel@nongnu.org; Fri, 17 Jun 2011 14:06:56 -0400 Received: from mail-vw0-f45.google.com ([209.85.212.45]:34940) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QXdRX-0006Vx-HF for qemu-devel@nongnu.org; Fri, 17 Jun 2011 14:06:55 -0400 Received: by vws17 with SMTP id 17so1057953vws.4 for ; Fri, 17 Jun 2011 11:06:54 -0700 (PDT) Sender: Richard Henderson Message-ID: <4DFB97B9.2030205@twiddle.net> Date: Fri, 17 Jun 2011 11:06:49 -0700 From: Richard Henderson MIME-Version: 1.0 References: <4DF9CD7E.5020509@siemens.com> <4DFB1D9D.7060108@siemens.com> In-Reply-To: <4DFB1D9D.7060108@siemens.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] Register Linux dyntick timer as per-thread signal List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Paolo Bonzini , Anthony Liguori , qemu-devel , kvm , Sasha Levin 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 Reviewed-by: Richard Henderson r~