From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=43170 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PjpCO-0004kV-KV for qemu-devel@nongnu.org; Mon, 31 Jan 2011 03:33:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PjpCN-0000eY-Ec for qemu-devel@nongnu.org; Mon, 31 Jan 2011 03:33:24 -0500 Received: from hall.aurel32.net ([88.191.126.93]:33170) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PjpCN-0000eI-A2 for qemu-devel@nongnu.org; Mon, 31 Jan 2011 03:33:23 -0500 Date: Mon, 31 Jan 2011 09:33:22 +0100 From: Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH 5/7] tcg-i386: Implement deposit operation. Message-ID: <20110131083322.GA17924@volta.aurel32.net> References: <1294716228-9299-1-git-send-email-rth@twiddle.net> <1294716228-9299-6-git-send-email-rth@twiddle.net> <20110125122749.GA19736@edde.se.axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20110125122749.GA19736@edde.se.axis.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Edgar E. Iglesias" Cc: agraf@suse.de, qemu-devel@nongnu.org, Richard Henderson Hi, On Tue, Jan 25, 2011 at 01:27:49PM +0100, Edgar E. Iglesias wrote: > On Mon, Jan 10, 2011 at 07:23:46PM -0800, Richard Henderson wrote: > > Special case deposits that are implementable with byte and word stores. > > Otherwise implement with double-word shift plus rotates. > > > > Expose tcg_scratch_alloc to the backend for allocation of scratch registers. > > > > Signed-off-by: Richard Henderson > > Hi, > > I've tested this patch a bit and got mixed results. I tested with patched > CRIS and MicroBlaze translators. The patch works OK (it doesn't break > anything) for the usecases I had but I saw a bit of a slowdown with > MicroBlaze (compare to not using deposit at all). > This week-end I have tested it emulating an x86-64 machine on x86-64, with all the patch series applied. I have measured the boot time from the bootloader up to the graphical environment of a Debian installation I used -snapshot to make sure the host hard-drive is not introducing any noise in the measurement (so that the whole image is in the host cache), and did the measurement 10 times. The machine is a Core 2 Q9650, nothing else was running on the machine except the few standard daemons. I have found that the boot time is roughly 1.8% faster with the patch series applied. It's undoubtedly an improvement, but still close to the measurement noise. This is a bit disappointing... -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurelien@aurel32.net http://www.aurel32.net