Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755991AbcJRGPe (ORCPT ); Tue, 18 Oct 2016 02:15:34 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:33304 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758272AbcJRGPB (ORCPT ); Tue, 18 Oct 2016 02:15:01 -0400 Subject: Re: [patch] perf_event_open.2: PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT To: Vince Weaver References: Cc: mtk.manpages@gmail.com, linux-man@vger.kernel.org, linux-kernel@vger.kernel.org, Kan Liang , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar From: "Michael Kerrisk (man-pages)" Message-ID: <0e5174be-17cd-83a5-3e1d-29d5ae720224@gmail.com> Date: Tue, 18 Oct 2016 08:14:56 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 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 Content-Length: 1513 Lines: 49 Hi Vince, On 10/17/2016 04:50 PM, Vince Weaver wrote: > > Linux 4.2 reserved a new bit from the misc field in the perf_event_open > mmap sample buffer: > PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT > > Despite being reserved in the public include/uapi/linux/perf_event.h > header file, this bit is never set by the kernel, rather it is used > internally by the userspace "perf" utility to indicate that when > attempting to parse all of the /proc/xxx/maps files for the sample > it ended up taking too long so the scan was aborted. > > Signed-off-by: Vince Weaver Thanks. Applied! Cheers, Michael > diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 > index fa8b1bd..59ad289 100644 > --- a/man2/perf_event_open.2 > +++ b/man2/perf_event_open.2 > @@ -1822,6 +1822,14 @@ See also > .BR PERF_RECORD_MISC_EXT_RESERVED " (since Linux 2.6.35)" > .\" commit 1676b8a077c352085d52578fb4f29350b58b6e74 > This indicates there is extended data available (currently not used). > +.TP > +.B PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT > +.\" commit 930e6fcd2bcce9bcd9d4aa7e755678d33f3fe6f4 > +This bit is not set by the kernel. > +It is reserved for the userspace perf utility to indicate that > +.I /proc/xxx/maps > +parsing was taking too long and stopped and thus the mmap > +records may be truncated. > .RE > .TP > .I type > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/