From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 3/3] perf, tools: Add support for guest/host-only profiling Date: Tue, 10 May 2011 18:09:46 +0200 Message-ID: <1305043786.2914.115.camel@laptop> References: <1305038132-5080-1-git-send-email-joerg.roedel@amd.com> <1305038132-5080-4-git-send-email-joerg.roedel@amd.com> <1305039008.2914.98.camel@laptop> <20110510150821.GC30996@amd.com> <1305041114.2914.105.camel@laptop> <20110510154652.GF30996@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" To: "Roedel, Joerg" Return-path: Received: from casper.infradead.org ([85.118.1.10]:40240 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932457Ab1EJQGp (ORCPT ); Tue, 10 May 2011 12:06:45 -0400 Received: from j77219.upc-j.chello.nl ([24.132.77.219] helo=dyad.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.72 #1 (Red Hat Linux)) id 1QJpSX-000303-HI for kvm@vger.kernel.org; Tue, 10 May 2011 16:06:53 +0000 In-Reply-To: <20110510154652.GF30996@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, 2011-05-10 at 17:46 +0200, Roedel, Joerg wrote: > > I intended to re-use the exlude_hv bit originally, but then I looked > into how this bit is used. On PPC it looks like this bit is set when > Linux itself runs as a guest to exclude the hypervisor code being > profiled. The meaning here is different (beacause Linux itself is the > hypervisor) and I wanted to avoid different semantics for this bit > across architectures. So I introduces seperate bits. > The exclude_hv bit can be used when we have some kind of perf-ctr > support for KVM guests. Ah, I didn't mean it like that, yes HV is strictly something different (and you understood its purpose well, its when the 'host' is a guest itself). What I was wondering about is if we want HV to be included in the Guest/Host exclusion mask or not. Then again, I guess that'll change behaviour in non-obvious ways, so better not do that.