Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752342AbaKUUCf (ORCPT ); Fri, 21 Nov 2014 15:02:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32881 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752030AbaKUUCe (ORCPT ); Fri, 21 Nov 2014 15:02:34 -0500 Date: Fri, 21 Nov 2014 15:00:52 -0500 From: Dave Jones To: Linus Torvalds Cc: Steven Rostedt , Andy Lutomirski , Tejun Heo , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Arnaldo Carvalho de Melo , Peter Zijlstra , Frederic Weisbecker , Don Zickus , the arch/x86 maintainers , Josh Boyer , Justin Forbes Subject: Re: frequent lockups in 3.18rc4 Message-ID: <20141121200052.GA28668@redhat.com> Mail-Followup-To: Dave Jones , Linus Torvalds , Steven Rostedt , Andy Lutomirski , Tejun Heo , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Arnaldo Carvalho de Melo , Peter Zijlstra , Frederic Weisbecker , Don Zickus , the arch/x86 maintainers , Josh Boyer , Justin Forbes References: <20141121170805.GD30603@home.goodmis.org> <20141121142301.564f7eb7@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 21, 2014 at 11:46:57AM -0800, Linus Torvalds wrote: > Anybody who seriously does virtualization uses hw virtualization that > is much better than it used to be. And the non-serious users aren't > that performance-sensitive by definition. > > I note that the Fedora kernel config seems to include paravirt by > default, so you get a lot of the crazy overheads.. I'm not sure how many people actually use paravirt these days, but the reason Fedora has it enabled still at least is probably because.. config KVM_GUEST bool "KVM Guest support (including kvmclock)" depends on PARAVIRT But tbh I've not looked at this stuff since it first got merged. Will a full-virt system kvm boot a guest without KVM_GUEST enabled ? (ie, is this just an optimisation for the paravirt case?) I'm not a heavy virt user, so I don't even remember how a lot of this stuff is supposed to work. Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/