From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753068AbbJNGdt (ORCPT ); Wed, 14 Oct 2015 02:33:49 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:37383 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752664AbbJNGdp (ORCPT ); Wed, 14 Oct 2015 02:33:45 -0400 Message-ID: <561DF746.3090403@gmail.com> Date: Wed, 14 Oct 2015 08:33:42 +0200 From: "Michael Kerrisk (man-pages)" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Vince Weaver CC: mtk.manpages@gmail.com, linux-man@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Stephane Eranian , Alexander Shishkin , Borislav Petkov , Frederic Weisbecker , "H. Peter Anvin" , Kaixu Xia , Linus Torvalds , Mike Galbraith , Robert Richter , Thomas Gleixner , adrian.hunter@intel.com, kan.liang@intel.com, markus.t.metzger@intel.com, mathieu.poirier@linaro.org Subject: Re: [patch 07/11] perf_event_open.2: 4.1 add AUX_FLAG_OVERWRITE support References: In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/23/2015 07:13 PM, Vince Weaver wrote: > > This manpage patch relates to the addition of the AUX sample flag > AUX_FLAG_OVERWRITE as added in the following commit: Thanks, Vince. Applied. Cheers, Michael > commit 2023a0d2829e521fe6ad6b9907f3f90bfbf57142 > Author: Alexander Shishkin > > perf: Support overwrite mode for the AUX area > > Signed-off-by: Alexander Shishkin > Signed-off-by: Peter Zijlstra (Intel) > Cc: Borislav Petkov > Cc: Frederic Weisbecker > Cc: H. Peter Anvin > Cc: Kaixu Xia > Cc: Linus Torvalds > Cc: Mike Galbraith > Cc: Paul Mackerras > Cc: Robert Richter > Cc: Stephane Eranian > Cc: Thomas Gleixner > Cc: acme@infradead.org > Cc: adrian.hunter@intel.com > Cc: kan.liang@intel.com > Cc: markus.t.metzger@intel.com > Cc: mathieu.poirier@linaro.org > Link: http://lkml.kernel.org/r/1421237903-181015-9-git-send-email-alexander.shishkin@linux.intel.com > Signed-off-by: Ingo Molnar > > Signed-off-by: Vince Weaver > > diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 > index dfb0b64..238eb62 100644 > --- a/man2/perf_event_open.2 > +++ b/man2/perf_event_open.2 > @@ -1670,6 +1670,15 @@ rlimit as well as the > .I perf_event_mlock_kb > allowance. > > +By default the AUX buffer will be truncated if it will not fit > +in the available space in the ring buffer. > +If the AUX buffer is mapped as a read only buffer, then it will > +operate in ring buffer mode where old data will be overwritten > +by new. > +In overwrite mode it might not be possible to infer where the > +new data began, and it is the consumer's job to disable > +measurement while reading to avoid possible data races. > + > The > .IR aux_head " and " aux_tail > ring buffer pointers have the same behavior and ordering > @@ -2476,6 +2485,10 @@ describes the aux update. > .B PERF_AUX_FLAG_TRUNCATED > if set then the data returned was truncated to fit the available > buffer size. > +.TP > +.B PERF_AUX_FLAG_OVERWRITE > +.\" commit 2023a0d2829e521fe6ad6b9907f3f90bfbf57142 > +if set then the data returned has overwritten previous data. > .RE > .RE > .RE > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/