From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=45072 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OgkOK-0003Sc-F8 for qemu-devel@nongnu.org; Wed, 04 Aug 2010 16:16:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OgkOJ-0004EH-6b for qemu-devel@nongnu.org; Wed, 04 Aug 2010 16:16:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52565) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OgkOI-0004EC-Un for qemu-devel@nongnu.org; Wed, 04 Aug 2010 16:16:43 -0400 Date: Wed, 4 Aug 2010 21:16:33 +0100 From: "Richard W.M. Jones" Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? Message-ID: <20100804201633.GA14048@amd.home.annexia.org> References: <4C5970AC.6060105@codemonkey.ws> <4C5995B4.90505@redhat.com> <4C5996F4.6010205@redhat.com> <721C3046-D6A7-47B2-A18C-4E59F2B68797@suse.de> <4C599B45.6030808@redhat.com> <966B1FAB-7E03-4EA6-AC74-767FC400A9CC@suse.de> <4C599FF3.5070208@redhat.com> <3A326B27-9204-4733-A9B6-25EC44291499@suse.de> <4C59A491.7020904@redhat.com> <4C59C862.60608@cisco.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C59C862.60608@cisco.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "David S. Ahern" Cc: kvm@vger.kernel.org, Gleb Natapov , qemu-devel@nongnu.org, Alexander Graf , Gerd Hoffmann , Avi Kivity On Wed, Aug 04, 2010 at 02:06:58PM -0600, David S. Ahern wrote: > > > On 08/04/10 11:34, Avi Kivity wrote: > > >> And it's awesome for fast prototyping. Of course, once that fast > >> becomes dog slow, it's not useful anymore. > > > > For the Nth time, it's only slow with 100MB initrds. > > 100MB is really not that large for an initrd. I'd just like to note that the libguestfs initrd is uncompressed. The reason for this is I found that the decompression code in Linux is really slow. I have to admit I didn't look into why this is. By not compressing it on the host and decompressing it on the guest, we saved a bunch of boot time (3-5 seconds IIRC). Anyway, comparing 115MB libguestfs initrd and other initrd sizes may not be a fair comparison, since almost every other initrd you will see will be compressed. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into Xen guests. http://et.redhat.com/~rjones/virt-p2v