Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757465Ab3JQP5W (ORCPT ); Thu, 17 Oct 2013 11:57:22 -0400 Received: from mail-oa0-f44.google.com ([209.85.219.44]:65125 "EHLO mail-oa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756295Ab3JQP5U (ORCPT ); Thu, 17 Oct 2013 11:57:20 -0400 MIME-Version: 1.0 In-Reply-To: <52600821.9010304@gmail.com> References: <20131017142839.GA8482@quad> <52600821.9010304@gmail.com> Date: Thu, 17 Oct 2013 17:57:20 +0200 Message-ID: Subject: Re: [PATCH v2] perf: disable PERF_RECORD_MMAP2 support From: Stephane Eranian To: David Ahern Cc: LKML , "mingo@elte.hu" , Peter Zijlstra , "ak@linux.intel.com" , Jiri Olsa , Arnaldo Carvalho de Melo , Hugh Dickins Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1593 Lines: 40 On Thu, Oct 17, 2013 at 5:54 PM, David Ahern wrote: > On 10/17/13 8:28 AM, Stephane Eranian wrote: >> >> >> For now, we disable the extended MMAP record support (MMAP2). >> We have identified cases where it would not report the correct >> mapping information, clone(VM_CLONE) but with separate pids. >> We will revisit the support once we find a solution for this case. >> >> The patch changes the kernel to return EINVAL if attr->mmap2 >> is set. The patch also modifies the perf tool to use regular >> PERF_RECORD_MMAP >> for synthetic events and it also prevents the tool from requesting >> attr->mmap2 >> mode because the kernel would reject it. >> >> The support will be revisited once the kenrel interface is updated. > > > Why not disable mmap2 as well: > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 0ce9febf1ba0..289f34dbe970 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -678,7 +678,7 @@ void perf_evsel__config(struct perf_evsel *evsel, > attr->sample_type |= PERF_SAMPLE_WEIGHT; > > attr->mmap = track; > - attr->mmap2 = track && !perf_missing_features.mmap2; > + /* attr->mmap2 = track && !perf_missing_features.mmap2; */ > attr->comm = track; > It is disabled automatically later on. I checked that. Wanted to minimize the changes. -- 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/