From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=36315 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PmpDV-0000He-4o for qemu-devel@nongnu.org; Tue, 08 Feb 2011 10:10:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PmpCD-0006Xi-Mu for qemu-devel@nongnu.org; Tue, 08 Feb 2011 10:09:40 -0500 Received: from hall.aurel32.net ([88.191.126.93]:58499) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PmpCD-0006Xb-En for qemu-devel@nongnu.org; Tue, 08 Feb 2011 10:09:37 -0500 Message-ID: <4D515CAB.6040700@aurel32.net> Date: Tue, 08 Feb 2011 16:09:31 +0100 From: Aurelien Jarno MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [PATCH 2/7] Enable I/O thread and VNC threads by default References: <4D3DFD20.8060004@linux.vnet.ibm.com> <20110125091741.GB30239@edde.se.axis.com> <20110125133453.GC5427@amt.cnet> <20110207101255.GA20413@amt.cnet> <20110207160350.GA26332@amt.cnet> <4D501C71.7090708@redhat.com> <4D50279B.5010102@siemens.com> <4D505DCB.9050406@codemonkey.ws> <20110207214551.GB16429@hall.aurel32.net> <4D50A5F0.802@codemonkey.ws> <20110208072657.GD16429@hall.aurel32.net> <4D50FA14.5010100@redhat.com> <4D5103E8.6050808@siemens.com> <4D510771.3040309@aurel32.net> <4D511221.9030505@siemens.com> <4D5113D3.9090802@aurel32.net> <4D511500.1040303@siemens.com> <4D5115C2.6060008@aurel32.net> <4D51842C.8000209@codemonkey.ws> <4D5125E2.8090902@aurel32.net> <4D5196DE.6030009@codemonkey.ws> <4D514558.9010003@aurel32.net> <4D51AD7D.6060709@codemonkey.ws> In-Reply-To: <4D51AD7D.6060709@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Stefan Hajnoczi , Jan Kiszka , Marcelo Tosatti , "qemu-devel@nongnu.org" , Anthony Liguori , Paul Brook , Paolo Bonzini , "Edgar E. Iglesias" , Arun Bharadwaj Anthony Liguori a écrit : > On 02/08/2011 07:30 AM, Aurelien Jarno wrote: >> So the strategy is let's break everything and wait for the maintainer to >> fix that? This strategy doesn't work, we have seen for example that with >> the SeaBIOS switch. While it brings nice features, it has broken the >> isapc machine. And it's still not fixed... >> > > The fundamental problem is that poorly thought out features have been > committed in the past. isapc is a good example of this. > > You can't just remove a chipset but leave an ISA bus implementation and > expect things to just keep working. Even the early ISA-only systems had > a chipset that firmware interfaced with. > >> Also this strategy doesn't scale, then the maintainers are spending >> their time fixing bugs introduced because others didn't care. Resources >> are not unlimited, especially for those doing that on their free time. >> > > So are you suggesting that every half baked feature should hold up any > other future developments? I think the real problem is exactly the > opposite of what you describe. Why should we waste finite resources > keeping something like Windows support limping along? > > We need to do a better job of not adding features that there is no > serious intention of every supporting in a meaningful way. I think the > recent discussion of w64 is a good example of this. I can't imagine > trying to support w64 in QEMU until someone actually makes w32 work in a > reasonable way. Yes, we should at least leave people time to find a solution. If nobody comes with a solution, let's consider it deprecated. >>> I think we've fixed all that we're aware of but we probably won't find >>> the rest unless we enable it universally. >>> >> I agree that we are going to discover bugs, and it's normal. QEMU is >> quite complex and it's not possible to test every combination. That said >> we are already aware of some bugs, why not fix them, or at least try to >> fix them? For example we haven't fixed the performance regression with >> TCG (at least it wasn't the case two weeks ago). >> > > If there are known issues, yes, let's fix them before enabling it. > So please look at this TCG performance regression instead of talking about enabling this just after the release. I don't consider TCG a half baked feature, for people who forgot about that it's the original QEMU mode. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurelien@aurel32.net http://www.aurel32.net