From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932859AbaFSOks (ORCPT ); Thu, 19 Jun 2014 10:40:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40250 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932138AbaFSOkp (ORCPT ); Thu, 19 Jun 2014 10:40:45 -0400 Message-ID: <53A2F63D.6010704@redhat.com> Date: Thu, 19 Jun 2014 16:39:57 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Andi Kleen , Eric Northup CC: Peter Zijlstra , gleb@kernel.org, Stephane Eranian , KVM , Linux Kernel Mailing List , Andi Kleen Subject: Re: [PATCH 4/4] kvm: Implement PEBS virtualization References: <1401412327-14810-1-git-send-email-andi@firstfloor.org> <1401412327-14810-5-git-send-email-andi@firstfloor.org> <20140602195711.GQ25366@two.firstfloor.org> In-Reply-To: <20140602195711.GQ25366@two.firstfloor.org> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 02/06/2014 21:57, Andi Kleen ha scritto: > > It would be a bigger concern if we expected virtual PMU migration to > > work, but I think it would be nice to update kvm_pmu_cpuid_update() to > > notice the presence/absence of the new CPUID bits, and then store that > > into per-VM kvm_pmu->pebs_allowed rather than relying only on the > > per-host perf_pebs_virtualization(). > > I hope at some point it can work. There shouldn't be any problems > with migrating to the same CPU model, in many cases (same event > and same PEBS format) it'll likely even work between models or > gracefully degrade. The code is there in both kernel and QEMU, it's just very little tested. Paolo