From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:57945) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q9SUT-0003hn-5n for qemu-devel@nongnu.org; Mon, 11 Apr 2011 21:34:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Q9OIf-0006q2-0B for qemu-devel@nongnu.org; Mon, 11 Apr 2011 17:05:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51764) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q9OIe-0006n8-Nc for qemu-devel@nongnu.org; Mon, 11 Apr 2011 17:05:32 -0400 Date: Mon, 11 Apr 2011 18:05:23 -0300 From: Luiz Capitulino Message-ID: <20110411180523.219530d7@doriath> In-Reply-To: <4DA35EE4.6090303@web.de> References: <20110408202525.26c45c05@doriath> <4D9FAD71.5020503@codemonkey.ws> <20110411153519.37f8316a@doriath> <1302548432.3589.78.camel@x201> <20110411161555.49688970@doriath> <4DA35EE4.6090303@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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, blauwirbel@gmail.com, Alex Williamson , avi@redhat.com On Mon, 11 Apr 2011 22:04:52 +0200 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? Still fast, but just realized that qemu-kvm's configure says that I/O thread is disabled: IO thread no And it's fast.. > > > > > 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. > > Jan >