From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MG7KQ-0001Mc-4J for qemu-devel@nongnu.org; Mon, 15 Jun 2009 04:14:06 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MG7KK-0001B0-RR for qemu-devel@nongnu.org; Mon, 15 Jun 2009 04:14:05 -0400 Received: from [199.232.76.173] (port=38311 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MG7KK-0001Ao-MB for qemu-devel@nongnu.org; Mon, 15 Jun 2009 04:14:00 -0400 Received: from smtp-4.hut.fi ([130.233.228.94]:53707) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MG7KJ-0004o6-LU for qemu-devel@nongnu.org; Mon, 15 Jun 2009 04:14:00 -0400 Subject: Re: [Qemu-devel] [PATCH] Instruction counting instrumentation for ARM, 2nd version From: Sami Kiminki In-Reply-To: <20090612154125.GD18247@shareable.org> References: <1244804168.7242.186.camel@dis> <20090612154125.GD18247@shareable.org> Content-Type: text/plain Date: Mon, 15 Jun 2009 11:12:00 +0300 Message-Id: <1245053520.28612.17.camel@dis> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jamie Lokier Cc: qemu-devel@nongnu.org On Fri, 2009-06-12 at 16:41 +0100, Jamie Lokier wrote: > Sami Kiminki wrote: > > What we would really like to see is a more general instrumentation > > framework, not just instruction counting and not just for ARM targets. > > The reason for this is that many measurements are so much easier to do > > in emulated/simulated environment than in real HW (e.g. instruction > > counting) and doing them in QEMU is way faster than using an ISA > > interpreter such as Valgrind. Some other instrumentation examples that > > come to my mind are cache usage efficiency analysis, branch profiling, > > and naturally instruction and memory access tracing. > > Valgrind isn't an interpreter. It's a JIT compiler like QEMU's TCG, > so are you sure these things are way faster in QEMU? No, not anymore. Thanks for correcting ;) However, what would still speak in favor of having some instrumentation support in QEMU, is measuring things at system-level. I assume this is pretty high in embedded system developers' wish-list. > What might work better would be to share some code from Valgrind/Cachegrind. Obviously. - Sami