From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54696) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TLdH3-0005w2-3u for qemu-devel@nongnu.org; Tue, 09 Oct 2012 13:07:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TLdGx-0005Yx-P4 for qemu-devel@nongnu.org; Tue, 09 Oct 2012 13:07:17 -0400 Received: from hall.aurel32.net ([88.191.126.93]:60155) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TLdGx-0005YQ-JG for qemu-devel@nongnu.org; Tue, 09 Oct 2012 13:07:11 -0400 Date: Tue, 9 Oct 2012 19:06:59 +0200 From: Aurelien Jarno Message-ID: <20121009170659.GE9643@ohm.aurel32.net> References: <1349481605-9561-1-git-send-email-rth@twiddle.net> <20121006101516.GK4623@ohm.aurel32.net> <20121008061747.GE4055@ohm.aurel32.net> <5074568C.20602@twiddle.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <5074568C.20602@twiddle.net> Subject: Re: [Qemu-devel] [PATCH] target-sparc register window handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson Cc: Blue Swirl , qemu-devel@nongnu.org On Tue, Oct 09, 2012 at 09:53:32AM -0700, Richard Henderson wrote: > On 10/07/2012 11:17 PM, Aurelien Jarno wrote: > > For what it worth, I measure a 4% slow down booting a sparc64 guest on a > > Core-i5 2500 machine. I guess the memcpy() of the register windows is > > more expensive that the gain on the TCG side, though it should be > > probably be confirmed using some profiling tools. > > Confirmed with userland testing (running cc1plus on large input), > and I see much more than 4% slow down -- more like 15%. I can reduce Not surprising. System mode spends a lot of time outside of the TCG code, and when doing TCG code, it spends most of its time in the qemu_ld/st code. User mode has a very simple qemu_ld/st code. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurelien@aurel32.net http://www.aurel32.net