From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32900) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XjYGY-00011h-KH for qemu-devel@nongnu.org; Wed, 29 Oct 2014 14:46:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XjYGP-0008Iz-Gx for qemu-devel@nongnu.org; Wed, 29 Oct 2014 14:46:42 -0400 Received: from mail-lb0-x236.google.com ([2a00:1450:4010:c04::236]:40589) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XjYGP-0008Iq-9R for qemu-devel@nongnu.org; Wed, 29 Oct 2014 14:46:33 -0400 Received: by mail-lb0-f182.google.com with SMTP id f15so3343341lbj.27 for ; Wed, 29 Oct 2014 11:46:32 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <54513602.3090306@redhat.com> Date: Wed, 29 Oct 2014 19:46:26 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <54511E21.10208@gmail.com> In-Reply-To: <54511E21.10208@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Timer list lock contention List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Sergey Fedorov , qemu-devel@nongnu.org On 10/29/2014 06:04 PM, Sergey Fedorov wrote: > Hi! > > I am wondering is there any case when timer list lock could be under > contention? Most of the time, the timer list is accessed under the "big QEMU lock" (qemu_mutex_lock_iothread/qemu_mutext_unlock_iothread), so the timer list lock itself shouldn't have contention at all. That said, there are plans to decrease the cost of the lock by not taking it at all in some cases. Paolo