From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932278AbbLNJzn (ORCPT ); Mon, 14 Dec 2015 04:55:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36268 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932150AbbLNJzl (ORCPT ); Mon, 14 Dec 2015 04:55:41 -0500 Date: Mon, 14 Dec 2015 10:55:38 +0100 From: Jiri Olsa To: Andi Kleen Cc: acme@kernel.org, jolsa@kernel.org, mingo@kernel.org, linux-kernel@vger.kernel.org, Andi Kleen Subject: Re: [PATCH] perf, tools: Disable branch flags/cycles for --callgraph lbr Message-ID: <20151214095538.GB27640@krava.brq.redhat.com> References: <1449879144-29074-1-git-send-email-andi@firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1449879144-29074-1-git-send-email-andi@firstfloor.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 11, 2015 at 04:12:24PM -0800, Andi Kleen wrote: > From: Andi Kleen > > [The kernel patch needed for this is in tip now > (b16a5b52eb9 perf/x86: Add option to disable ...) > So this user tools patch to make use of it should be merged now] > > Automatically disable collecting branch flags and cycles with > --call-graph lbr. This allows avoiding a bunch of extra MSR > reads in the PMI on Skylake. > > When the kernel doesn't support the new flags they are automatically > cleared in the fallback code. > > v2: Switch to use branch_sample_type instead of sample_type. > Adjust description. > Fix the fallback logic. > Signed-off-by: Andi Kleen Acked-by: Jiri Olsa thanks, jirka