From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752507Ab2LPJEW (ORCPT ); Sun, 16 Dec 2012 04:04:22 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:34237 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752271Ab2LPJEQ (ORCPT ); Sun, 16 Dec 2012 04:04:16 -0500 Date: Sun, 16 Dec 2012 10:04:10 +0100 From: Ingo Molnar To: suravee.suthikulpanit@amd.com Cc: a.p.zijlstra@chello.nl, paulus@samba.org, mingo@redhat.com, acme@ghostprotocols.net, tglx@linutronix.de, hpa@zytor.com, rric@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, jacob.shin@amd.com Subject: Re: [PATCH 1/1] Change IBS PMU to use perf_hw_context Message-ID: <20121216090410.GC21690@gmail.com> References: <1355518662-32071-1-git-send-email-suravee.suthikulpanit@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1355518662-32071-1-git-send-email-suravee.suthikulpanit@amd.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * suravee.suthikulpanit@amd.com wrote: > From: Suravee Suthikulpanit > > Currently, the AMD IBS PMU initialize pmu.task_ctx_nr to > perf_invalid_context which only allows IBS to be running only > in system-wide mode (e.g. perf record -a). IBS hardware is > available in each core and should be per-context. This patch > modifies the task_ctx_nr to use the perf_hw_context (default) > instead. I'm wondering how extensively was it tested/verified that it's safe to enable IBS in per context mode as well, and that the profiling results are precise and accurate? We never used the IBS hardware in this fashion before, so some extra care is prudent - and traces of that extra care should be visible in the changelog as well. Thanks, Ingo