From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1IUkz9-0001oq-Tp for qemu-devel@nongnu.org; Mon, 10 Sep 2007 11:15:36 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1IUkz9-0001oW-BN for qemu-devel@nongnu.org; Mon, 10 Sep 2007 11:15:35 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IUkz9-0001oQ-4O for qemu-devel@nongnu.org; Mon, 10 Sep 2007 11:15:35 -0400 Received: from mail.codesourcery.com ([65.74.133.4]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1IUkz8-0003w4-C0 for qemu-devel@nongnu.org; Mon, 10 Sep 2007 11:15:34 -0400 From: Paul Brook Subject: Re: [Qemu-devel] Performance counter Date: Mon, 10 Sep 2007 16:15:22 +0100 References: <1189388998.21397.6.camel@localhost> <5b31733c0709100146jf4f22f6l900dc55edf38f9d0@mail.gmail.com> In-Reply-To: <5b31733c0709100146jf4f22f6l900dc55edf38f9d0@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200709101615.23250.paul@codesourcery.com> 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 Cc: Filip Navara > > I'm using qemu at the moment to run a system for debugging purposes. I > > was wondering whether qemu does actually emulate the performance > > counters on IA32. Every time i try to read the value out, it > > consistently gives me zero even though i have written to the given model > > specific register. > > the performance registers aren't implemented on QEMU. QEMU is not cycle accurate, nor does it emulate memory caches or have an accurate TLB model, so I'm fairly sure we do can have provide meaningful values for most of the counters. Paul