From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NfUcs-00074h-G4 for qemu-devel@nongnu.org; Thu, 11 Feb 2010 03:42:19 -0500 Received: from [199.232.76.173] (port=53611 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NfUcq-00074G-Hr for qemu-devel@nongnu.org; Thu, 11 Feb 2010 03:42:17 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1NfUcn-0001br-50 for qemu-devel@nongnu.org; Thu, 11 Feb 2010 03:42:16 -0500 Received: from fe01x03-cgp.akado.ru ([77.232.31.164]:51163 helo=akado.ru) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NfUcm-0001bh-Nl for qemu-devel@nongnu.org; Thu, 11 Feb 2010 03:42:12 -0500 Date: Thu, 11 Feb 2010 11:42:03 +0300 (MSK) From: malc Subject: Re: [Qemu-devel] Audio latency In-Reply-To: <12d708831002102303t777e6f83g563311cc0f9cf1a1@mail.gmail.com> Message-ID: References: <12d708831002101540m1061cc8ag2e5d31c6d73f31c0@mail.gmail.com> <12d708831002102247n3438bf09h502d1f4050723f3d@mail.gmail.com> <12d708831002102303t777e6f83g563311cc0f9cf1a1@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alberich de megres Cc: qemu-devel@nongnu.org On Thu, 11 Feb 2010, Alberich de megres wrote: > On Thu, Feb 11, 2010 at 7:53 AM, malc wrote: > > On Thu, 11 Feb 2010, Alberich de megres wrote: > > > >> I'm using the alsa driver. > >> Even I tried to change some values using the export and some flags > >> that -audio-help shows, but nothing significant. > > > > Please do not top post. > > Sorrry!! > > > > >> > >> > >> On Thu, Feb 11, 2010 at 1:03 AM, malc wrote: > >> > On Thu, 11 Feb 2010, Alberich de megres wrote: > >> > > >> >> Hi! > >> >> > >> >> I'm running qemu on suse, and i got a very high audio latency. For > >> >> example, using windows latency is about 4s and audio gets distorted > >> >> with little cuts. > > > > How do you measure it? > With a program called dpc latency, it's for windows. > > > > >> >> On the host side (suse), i changed the audio pci device latency to 99 > >> >> but this only improves a little bit. > > > > As in: with setpci? > Yes. I also tired, on host, to low latency to VGA to 10. That's completely unrelated latency [1] > > > >> >> Other thing i noticed is when lowering video resolution, the audio > >> >> latency gets better and better. > > > > Lowering video resolution of what? Guest, host? > > Yes, it was on guest. Even for example if i change the desktop or > switch to a text terminal when things works better what suggested me > that could be something with painting the screen. But i'm not shure if > its just only a side effect of a bad launch command, or something > else. > > > > >> >> I started played with source code, but i'm just a newbie on qemu. > >> >> Anyone can point some light to me please? > >> >> > >> >> thanks guys!! > >> > > >> > -audio-help is your friend, from there you can deduce (at the very least) > >> > which audio driver your qemu uses. > >> > > > > > It would also help to know which version of QEMU you run and exactly how > > you invoke it. > > You're right..sorry: > > qemu-kvm -cpu core2duo -smp 2 -m 1024 -hda /home/nine/imgs/hda1.img > -vga std -usbdevice tablet > -name t1 -net nic,macaddr=55:54:00:12:34:56 -net > tap,ifname=tap1,script=no > -soundhw ac97 I can't help you with kvm and windows, that said here are the things to try: a. Vanilla qemu b. No smp And i'm not saying that those will help, just trying to collect more data points. P.S. 4 seconds of latency is sortof insane, especially given that default buffering for ALSA is nowhere near that, not by a longest shot. [1] http://www.reric.net/linux/pci_latency.html -- mailto:av1474@comtv.ru