From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:34083) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q9SGQ-00076X-GF for qemu-devel@nongnu.org; Mon, 11 Apr 2011 21:19:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Q9Re0-00009g-5f for qemu-devel@nongnu.org; Mon, 11 Apr 2011 20:39:49 -0400 Received: from mail-gy0-f173.google.com ([209.85.160.173]:60015) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q9Re0-00007g-2L for qemu-devel@nongnu.org; Mon, 11 Apr 2011 20:39:48 -0400 Received: by gyg4 with SMTP id 4so2960271gyg.4 for ; Mon, 11 Apr 2011 17:39:46 -0700 (PDT) Message-ID: <4DA39F50.8090108@codemonkey.ws> Date: Mon, 11 Apr 2011 19:39:44 -0500 From: Anthony Liguori MIME-Version: 1.0 References: <20110408202525.26c45c05@doriath> <4D9FAD71.5020503@codemonkey.ws> <20110411153519.37f8316a@doriath> <1302548432.3589.78.camel@x201> <20110411161555.49688970@doriath> <4DA35EE4.6090303@web.de> In-Reply-To: <4DA35EE4.6090303@web.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: kvm@vger.kernel.org, mst@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, Luiz Capitulino , blauwirbel@gmail.com, Alex Williamson , avi@redhat.com On 04/11/2011 03:04 PM, Jan Kiszka wrote: > On 2011-04-11 21:15, Luiz Capitulino wrote: >> On Mon, 11 Apr 2011 13:00:32 -0600 >> Alex Williamson wrote: >> >>> On Mon, 2011-04-11 at 15:35 -0300, Luiz Capitulino wrote: >>>> On Fri, 08 Apr 2011 19:50:57 -0500 >>>> Anthony Liguori wrote: >>>> >>>>> On 04/08/2011 06:25 PM, Luiz Capitulino wrote: >>>>>> Hi there, >>>>>> >>>>>> Summary: >>>>>> >>>>>> - PXE boot in qemu.git (HEAD f124a41) is quite slow, more than 5 minutes. Got >>>>>> the problem with e1000, virtio and rtl8139. However, pcnet *works* (it's >>>>>> as fast as qemu-kvm.git) >>>>>> >>>>>> - PXE boot in qemu-kvm.git (HEAD df85c051) is fast, less than a minute. Tried >>>>>> with e1000, virtio and rtl8139 (I don't remember if I tried with pcnet) >>>>>> >>> I was having this problem too, but I think it's because I forgot to >>> build qemu with --enable-io-thread, which is the default for qemu-kvm. >>> Can you re-configure and build with that and see if it's fast? Thanks, >> Yes, nice catch, it's faster with I/O thread enabled, even seem faster >> than qemu-kvm.git. > What's the performance under qemu-kvm with -no-kvm-irqchip? > >> So, does this have to be fixed w/o I/O thread? > If it's most probably an architectural deficit of non-io-thread mode, I > would say let it rest in peace. But maybe it points to a generic issues > that is just magnified by non-threaded mode. If gpxe is spinning waiting for I/O to complete, that's going to prevent select from running until the next signal (timer event). Regards, Anthony Liguori > Jan >