Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932557Ab2JDNHl (ORCPT ); Thu, 4 Oct 2012 09:07:41 -0400 Received: from casper.infradead.org ([85.118.1.10]:34519 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932407Ab2JDNHj convert rfc822-to-8bit (ORCPT ); Thu, 4 Oct 2012 09:07:39 -0400 Message-ID: <1349356038.14388.3.camel@twins> Subject: Re: [PATCH RFC 1/2] kvm: Handle undercommitted guest case in PLE handler From: Peter Zijlstra To: Avi Kivity Cc: Raghavendra K T , Rik van Riel , "H. Peter Anvin" , Ingo Molnar , Marcelo Tosatti , Srikar , "Nikunj A. Dadhania" , KVM , Jiannan Ouyang , chegu vinod , "Andrew M. Theurer" , LKML , Srivatsa Vaddagiri , Gleb Natapov Date: Thu, 04 Oct 2012 15:07:18 +0200 In-Reply-To: <506D83EE.2020303@redhat.com> References: <20120921115942.27611.67488.sendpatchset@codeblue> <20120921120000.27611.71321.sendpatchset@codeblue> <505C654B.2050106@redhat.com> <505CA2EB.7050403@linux.vnet.ibm.com> <50607F1F.2040704@redhat.com> <20121003122209.GA9076@linux.vnet.ibm.com> <506C7057.6000102@redhat.com> <506D69AB.7020400@linux.vnet.ibm.com> <506D83EE.2020303@redhat.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 659 Lines: 14 On Thu, 2012-10-04 at 14:41 +0200, Avi Kivity wrote: > > Again the numbers are ridiculously high for arch_local_irq_restore. > Maybe there's a bad perf/kvm interaction when we're injecting an > interrupt, I can't believe we're spending 84% of the time running the > popf instruction. Smells like a software fallback that doesn't do NMI, hrtimer based sampling typically hits popf where we re-enable interrupts. -- 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/