From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LcfbC-0008Ae-0d for qemu-devel@nongnu.org; Thu, 26 Feb 2009 07:44:22 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LcfbB-00088f-6n for qemu-devel@nongnu.org; Thu, 26 Feb 2009 07:44:21 -0500 Received: from [199.232.76.173] (port=42724 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LcfbB-00088N-2o for qemu-devel@nongnu.org; Thu, 26 Feb 2009 07:44:21 -0500 Received: from smtprelay10.ispgateway.de ([80.67.29.24]:43751) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LcfbA-0001VG-71 for qemu-devel@nongnu.org; Thu, 26 Feb 2009 07:44:20 -0500 Received: from [87.167.60.209] (helo=[192.168.187.102]) by smtprelay10.ispgateway.de with esmtpa (Exim 4.68) (envelope-from ) id 1Lcfb4-0001Ge-K0 for qemu-devel@nongnu.org; Thu, 26 Feb 2009 13:44:14 +0100 Message-ID: <49A68E9F.7030300@rbg.informatik.tu-darmstadt.de> Date: Thu, 26 Feb 2009 13:44:15 +0100 From: Alex-Uni MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Attempt for reproducible behavior Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Hello, I am trying to modify Qemu, so it offers reproducible behavior. I'm using the icounts for the time measurement. For example: I have a simple code which measures the time before the start of a loop. The loop runs for an definite amount of rounds. In this case I let it count to 100000000 in a while-loop. Then the codes measures the time after the loop. Both times in milliseconds. The time difference is about 5000 milliseconds. Now, while the loop is still running, i make a snapshot. Lets say at 2000 milliseconds. After loading this snapshot it the loop should run for 3000 milliseconds. But it doesnt, it's alway different. I figured, that it depends on the value of next_tb and therefor on tcg_qemu_tb_exec(tc_ptr) in line 615 in the cpu-exec.c. Now I have the problem, that I can't follow the code. I don't know why tcg_qemu_tb_exec(tc_ptr) produces different results and where to look. I only found the define in the tcg.h. Can somebody help me with this problem? I'm working on the svn-version 5806. Thank you Alex (Please CC: me when replying, I am not on the list)