From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=59672 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Ogh2i-0007rZ-Ua for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:42:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Ogh2f-0004SC-LY for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:42:10 -0400 Received: from mail-qy0-f173.google.com ([209.85.216.173]:62199) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Ogh2f-0004S0-JT for qemu-devel@nongnu.org; Wed, 04 Aug 2010 12:42:09 -0400 Received: by qyk35 with SMTP id 35so2039399qyk.4 for ; Wed, 04 Aug 2010 09:42:08 -0700 (PDT) Message-ID: <4C59985B.1050304@codemonkey.ws> Date: Wed, 04 Aug 2010 11:42:03 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? References: <20100803190525.GB16570@redhat.com> <4C586AB9.5040302@codemonkey.ws> <4C586CF9.7030206@redhat.com> <4C588804.5060803@redhat.com> <4C590046.2020705@redhat.com> <4C591D48.9080301@redhat.com> <4C592218.3000901@redhat.com> <4C596549.1070109@codemonkey.ws> <20100804130709.GL10499@redhat.com> <4C5967D8.7080707@codemonkey.ws> <20100804133401.GP10499@redhat.com> <4C5970AC.6060105@codemonkey.ws> <4C5995B4.90505@redhat.com> In-Reply-To: <4C5995B4.90505@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Gerd Hoffmann , Gleb Natapov , "Richard W.M. Jones" On 08/04/2010 11:30 AM, Avi Kivity wrote: > On 08/04/2010 04:52 PM, Anthony Liguori wrote: >>>> >>> This is not like DMA event if done in chunks and chunks can be pretty >>> big. The code that dials with copying may temporary unmap some pci >>> devices to have more space there. >> >> >> That's a bit complicated because SeaBIOS is managing the PCI devices >> whereas the kernel code is running as an option rom. I don't know >> the BIOS PCI interfaces well so I don't know how doable this is. >> >> Maybe we're just being too fancy here. >> >> We could rewrite -kernel/-append/-initrd to just generate a floppy >> image in RAM, and just boot from floppy. > > How could this work? the RAM belongs to SeaBIOS immediately after > reset, it would just scribble over it. Or worse, not scribble on it > until some date in the future. I mean host RAM, not guest RAM. Regards, Anthony Liguori > > -kernel data has to find its way to memory after the bios gives > control to some optionrom. An alternative would be to embed knowledge > of -kernel in seabios, but I don't think it's a good one. >