From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=40172 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Oal87-0008NE-6z for qemu-devel@nongnu.org; Mon, 19 Jul 2010 03:51:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Oal85-0005oI-Kw for qemu-devel@nongnu.org; Mon, 19 Jul 2010 03:51:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34647) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Oal85-0005oB-AN for qemu-devel@nongnu.org; Mon, 19 Jul 2010 03:51:13 -0400 Date: Mon, 19 Jul 2010 10:51:10 +0300 From: Gleb Natapov Subject: Re: [Qemu-devel] Question about qemu firmware configuration (fw_cfg) device Message-ID: <20100719075110.GB4689@redhat.com> References: <20100717095059.GA19767@amd.home.annexia.org> <20100717095353.GB19767@amd.home.annexia.org> <269D196D-8CE8-4E24-8EE1-39756AC55F7F@suse.de> <20100718200942.GL13194@amd.home.annexia.org> <44FD4F00-843D-41C8-B21A-148D16745015@suse.de> <20100719062356.GU4689@redhat.com> <20100719072802.GO13194@amd.home.annexia.org> <20100719073312.GY4689@redhat.com> <4E9BBBA5-F2D1-4485-AFD3-8D6FDE3A3CCC@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E9BBBA5-F2D1-4485-AFD3-8D6FDE3A3CCC@suse.de> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: "Richard W.M. Jones" , qemu-devel@nongnu.org On Mon, Jul 19, 2010 at 09:40:18AM +0200, Alexander Graf wrote: > > On 19.07.2010, at 09:33, Gleb Natapov wrote: > > > On Mon, Jul 19, 2010 at 08:28:02AM +0100, Richard W.M. Jones wrote: > >> On Mon, Jul 19, 2010 at 09:23:56AM +0300, Gleb Natapov wrote: > >>> That what I am warring about too. If we are adding device we have to be > >>> sure such device can actually exist on real hw too otherwise we may have > >>> problems later. > >> > >> I don't understand why the constraints of real h/w have anything to do > >> with this. Can you explain? > >> > > Each time we do something not architectural it cause us troubles later. > > So constraints of real h/w is our constrains to. > > > >>> Also 1 second on 100M file does not look like huge gain to me. > >> > >> Every second counts. We're trying to get libguestfs boot times down > >> from 8-12 seconds to 4-5 seconds. For many cases it's an interactive > >> program. > >> > > So what about making initrd smaller? I remember managing two > > distribution in 64M flash in embedded project. > > Having a huge initrd basically helps in reusing a lot of existing code. We do the same - in general the initrd is just a subset of the applications of the host OS. And if you start putting perl or the likes into it, it becomes big. > Why not provide small disk/cdrom with all those utilities installed? > I guess the best thing for now really is to try and see which code paths insb goes along. It should really be coalesced. > It is coalesced to a certain extent (reenter guest every 1024 bytes, read from userspace page at a time). You need to continue injecting interrupt into a guest during long string operation and checking exception condition on a page boundaries. > Richard, what does kvm_stat tell you while loading the initrd? Are there a lot of PIO requests or are we simply looping inside qemu code? > > > Alex -- Gleb.