From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932160Ab3BFVqD (ORCPT ); Wed, 6 Feb 2013 16:46:03 -0500 Received: from merlin.infradead.org ([205.233.59.134]:57292 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758769Ab3BFVod (ORCPT ); Wed, 6 Feb 2013 16:44:33 -0500 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Jiri Olsa , Andrew Jones , Corey Ashford , David Ahern , Frederic Weisbecker , Ingo Molnar , Namhyung Kim , Paul Mackerras , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 12/17] perf perl scripts: Fix SIGALRM and pipe read race for rwtop Date: Wed, 6 Feb 2013 18:44:14 -0300 Message-Id: <1360187059-12661-13-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.8.1.1.361.gec3ae6e In-Reply-To: <1360187059-12661-1-git-send-email-acme@infradead.org> References: <1360187059-12661-1-git-send-email-acme@infradead.org> Content-Type: text/plain; charset="utf-8" X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa Fixing rwtop script race. The issue is caused by rwtop script triggering SIGALRM and underneath pipe reading layer reporting error when interrupted. Fixing this by setting SA_RESTART for rwtop SIGALRM handler, which avoids interruption of the pipe reading layer. The discussion for this issue & fix is here: https://lkml.org/lkml/2012/9/18/123 Signed-off-by: Jiri Olsa Original-patch-by: Andrew Jones Cc: Andrew Jones Cc: Corey Ashford Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1360080351-3246-2-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/scripts/perl/rwtop.pl | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/scripts/perl/rwtop.pl b/tools/perf/scripts/perl/rwtop.pl index 4bb3ecd..8b20787 100644 --- a/tools/perf/scripts/perl/rwtop.pl +++ b/tools/perf/scripts/perl/rwtop.pl @@ -17,6 +17,7 @@ use lib "$ENV{'PERF_EXEC_PATH'}/scripts/perl/Perf-Trace-Util/lib"; use lib "./Perf-Trace-Util/lib"; use Perf::Trace::Core; use Perf::Trace::Util; +use POSIX qw/SIGALRM SA_RESTART/; my $default_interval = 3; my $nlines = 20; @@ -90,7 +91,10 @@ sub syscalls::sys_enter_write sub trace_begin { - $SIG{ALRM} = \&set_print_pending; + my $sa = POSIX::SigAction->new(\&set_print_pending); + $sa->flags(SA_RESTART); + $sa->safe(1); + POSIX::sigaction(SIGALRM, $sa) or die "Can't set SIGALRM handler: $!\n"; alarm 1; } -- 1.8.1.1.361.gec3ae6e