From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35365) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RqffV-000838-Od for qemu-devel@nongnu.org; Fri, 27 Jan 2012 01:52:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RqffU-0004Mn-6N for qemu-devel@nongnu.org; Fri, 27 Jan 2012 01:52:17 -0500 Received: from chello084112167138.7.11.vie.surfer.at ([84.112.167.138]:33164 helo=wiesinger.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RqffT-0004II-Oo for qemu-devel@nongnu.org; Fri, 27 Jan 2012 01:52:16 -0500 Date: Fri, 27 Jan 2012 07:50:10 +0100 (CET) From: Gerhard Wiesinger In-Reply-To: <4F21473B.2000703@redhat.com> Message-ID: References: <1326637051-23920-1-git-send-email-avi@redhat.com> <4F12E232.5090809@web.de> <4F130667.9050609@redhat.com> <4F21473B.2000703@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Subject: Re: [Qemu-devel] [PATCH] kvm: flush the dirty log when unregistering a slot List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Marcelo Tosatti , Jan Kiszka , qemu-devel@nongnu.org, kvm@vger.kernel.org On Thu, 26 Jan 2012, Avi Kivity wrote: > On 01/25/2012 10:15 PM, Gerhard Wiesinger wrote: >> On Sun, 15 Jan 2012, Avi Kivity wrote: >> >>> On 01/15/2012 04:40 PM, Gerhard Wiesinger wrote: >>>> On Sun, 15 Jan 2012, Jan Kiszka wrote: >>>> >>>>> On 2012-01-15 15:17, Avi Kivity wrote: >>>>>> Otherwise, the dirty log information is lost in the kernel forever. >>>>>> >>>>>> Fixes opensuse-12.1 boot screen, which changes the vga windows >>>>>> rapidly. >>>>> >>>>> Confirmed, problems solved here. >>>> >>>> Problem from: >>>> http://permalink.gmane.org/gmane.comp.emulators.qemu/131853 >>>> >>>> Confirmed to be fixed, too. Long awaited patch :-) >>> >>> Sorry, I forgot about that. Please ping me if I do that. >>> >>>> >>>> BTW: There is also a major difference in video performance: >>>> 1.) With Patch: 1400MB/s (MByte/s) >>>> 2.) Without Patch: 6MB/s >>>> >>>> Any reason for that? >>> >>> What are you measuring exactly? >> >> I'm measuring VGA video performance under DOS with own written test >> program. >> >> What's strange, new findings: Measurement doesn't depend on the patch. >> Sometimes it is high sometimes low. I think I have to investigate >> further. >> >> Any ideas? > > What vga mode are you using? What does the test program do? DOS Test programs, source and binaries can be found at: http://www.wiesinger.com/opensource/qemu/ 1.) Measures page A000:0000 with videomode 4F02, see: http://www.wiesinger.com/opensource/qemu/memperf.c 2.) Second test program measures setting and getting video bank, see: http://www.wiesinger.com/opensource/qemu/int10per.c We already talked about the low performance some time ago and tracked it down to kernel <=> userspace switching. But I benchmarked it already once and I think there are some optimizations possible (linear list search) with mapping functions (e.g. trivial hash function before) Thnx. Ciao, Gerhard -- http://www.wiesinger.com/