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authorJiri Olsa <jolsa@redhat.com>2013-02-05 17:05:50 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-02-06 18:09:27 -0300
commitb22e79395c0fe4c86dd35745a929366034386ccc (patch)
tree1096eeb6bb9c5237a33c206a02137e6dbd8cee5d /tools/perf/scripts
parent0c5268bf2218144469dde3228f14898fadbbcdcd (diff)
downloadlinux-b22e79395c0fe4c86dd35745a929366034386ccc.tar.gz
perf perl scripts: Fix SIGALRM and pipe read race for rwtop
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 <jolsa@redhat.com> Original-patch-by: Andrew Jones <drjones@redhat.com> Cc: Andrew Jones <drjones@redhat.com> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1360080351-3246-2-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/scripts')
-rw-r--r--tools/perf/scripts/perl/rwtop.pl6
1 files changed, 5 insertions, 1 deletions
diff --git a/tools/perf/scripts/perl/rwtop.pl b/tools/perf/scripts/perl/rwtop.pl
index 4bb3ecd33472..8b20787021c1 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;
}