From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Kt13B-0001Dp-N8 for qemu-devel@nongnu.org; Thu, 23 Oct 2008 10:20:33 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Kt13A-0001Cu-VP for qemu-devel@nongnu.org; Thu, 23 Oct 2008 10:20:33 -0400 Received: from [199.232.76.173] (port=40799 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Kt13A-0001Cb-Qf for qemu-devel@nongnu.org; Thu, 23 Oct 2008 10:20:32 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:46639) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1Kt13A-0001dh-QH for qemu-devel@nongnu.org; Thu, 23 Oct 2008 10:20:32 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e8.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id m9NEHE30030486 for ; Thu, 23 Oct 2008 10:17:14 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9NEKTdA042344 for ; Thu, 23 Oct 2008 10:20:29 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9NEKTrO023918 for ; Thu, 23 Oct 2008 10:20:29 -0400 Message-ID: <4900882A.30909@us.ibm.com> Date: Thu, 23 Oct 2008 09:20:26 -0500 From: Anthony Liguori MIME-Version: 1.0 References: <1224771556-11146-1-git-send-email-glommer@redhat.com> <1224771556-11146-21-git-send-email-glommer@redhat.com> In-Reply-To: <1224771556-11146-21-git-send-email-glommer@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH 20/32] accel_trace_io Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Glauber Costa Cc: jan.kiszka@siemens.com, jes@sgi.com, qemu-devel@nongnu.org, avi@qumranet.com, Glauber Costa , dmitry.baryshkov@siemens.com Glauber Costa wrote: > From: Glauber Costa > > kqemu keeps trace of the last io done. Do it through > an accel_wrapper. > The hooks here are probably not the best they could be. The purpose of this code in kqemu, from what I can tell, is to control how long we run in softmmu before trying to run in the kernel again. I presume this is mainly for kernel-kqemu. When kernel-kqemu encounters an instruction it can't handle, it drops to userspace and runs in softmmu for a while. The question is how long should it run in softmmu and this is a heuristic. This is what the code is doing. Regards, Anthony Liguori