From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=41336 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pi18O-0004mR-1l for qemu-devel@nongnu.org; Wed, 26 Jan 2011 03:53:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pi18L-0004C6-NS for qemu-devel@nongnu.org; Wed, 26 Jan 2011 03:53:47 -0500 Received: from mail-ew0-f45.google.com ([209.85.215.45]:44146) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pi18L-0004BQ-I6 for qemu-devel@nongnu.org; Wed, 26 Jan 2011 03:53:45 -0500 Received: by ewy10 with SMTP id 10so59994ewy.4 for ; Wed, 26 Jan 2011 00:53:43 -0800 (PST) Date: Wed, 26 Jan 2011 09:53:38 +0100 From: "Edgar E. Iglesias" Subject: Re: [Qemu-devel] [PATCH 5/7] tcg-i386: Implement deposit operation. Message-ID: <20110126085338.GA26088@laped.lan> 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> <4D3EF6C1.3080502@twiddle.net> <20110125164816.GA23569@laped.lan> <4D3F4993.4010109@twiddle.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D3F4993.4010109@twiddle.net> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson Cc: qemu-devel@nongnu.org, aurelien@aurel32.net, agraf@suse.de On Tue, Jan 25, 2011 at 02:07:15PM -0800, Richard Henderson wrote: > On 01/25/2011 08:48 AM, Edgar E. Iglesias wrote: > > OK, I see. Maybe we should try to emit an insn sequence more similar > > to what tcg was emitting (for the non 8 & 16-bit deposits)? > > That ought too at least give similar results as before for those and > > give us a speedup for the byte and word moves. > > Please try this replacement version for tcg/i386/*. > > I was able to run your cris testsuite, and stuff looked ok there. > But for some reason the microblaze kernel would not boot. It seems > that the kernel commandline isn't in place properly and it isn't > finding the disk image. Yes, you need to build qemu with libfdt for that image to boot. IIRC, libfdt comes with the dtc package on some dists. In the future I'll see if can upload an image that boots without the need of devicetree manipulation in qemu. I tried your new patch and got similar results as before. Maaybe slightly faster but within the noise. I looked a little bit more at it and realized that I'm probably not doing a fair comparition with microblaze. The write_carry sequence actually bit deposits a bit into two locations with a sequence of tcg ops that is not much longer than the one to deposit a single bit. So I'm basically comparing the cost of a single tcg deposit sequence with the cost of two tcg deposit backend ops. I should probably just accept that the new deposit op is not worth using for that particular case. It would be nice if somebody else also tested this patch. Before we agree on applying it. One note, the tcg_scratch_alloc hunk from the previous version was missing on this one. Thanks