From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753936Ab0CROgo (ORCPT ); Thu, 18 Mar 2010 10:36:44 -0400 Received: from casper.infradead.org ([85.118.1.10]:44827 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753946Ab0CROgm (ORCPT ); Thu, 18 Mar 2010 10:36:42 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, "Zhang, Yanmin" , Avi Kivity , Peter Zijlstra , Sheng Yang , Marcelo Tosatti , Joerg Roedel , Jes Sorensen , Gleb Natapov , Zachary Amsden , , Arnaldo Carvalho de Melo Subject: [PATCH 1/3] perf stat: Enable counters when collecting process-wide or system-wide data Date: Thu, 18 Mar 2010 11:36:03 -0300 Message-Id: <1268922965-14774-1-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.6.2.5 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.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: Zhang, Yanmin Command 'perf stat' doesn't enable counters when collecting an existing (by -p) process or a system-wide statistics. Fix the issue. Change the condition of fork/exec subcommand. If there is a subcommand parameter, perf always fork/exec it. The usage example is: # perf stat -a sleep 10 So this command could collect statistics for 10 seconds precisely. User still could stop it by CTRL+C. Without the new capability, user could only use CTRL+C to stop it without precise time clock. Another issue is 'perf stat -a' consumes 100% time of a full single logical cpu. It has a bad impact on running workload. Fix it by adding a sleep(1) in the while(!done) loop in function run_perf_stat. Signed-off-by: Zhang Yanmin Cc: Avi Kivity Cc: Peter Zijlstra Cc: Sheng Yang Cc: Marcelo Tosatti Cc: Joerg Roedel Cc: Jes Sorensen Cc: Gleb Natapov Cc: Zachary Amsden Cc: Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 24 ++++++++++++++---------- 1 files changed, 14 insertions(+), 10 deletions(-) diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 95db31c..5f41244 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -159,8 +159,10 @@ static void create_perf_stat_counter(int counter, int pid) } } else { attr->inherit = inherit; - attr->disabled = 1; - attr->enable_on_exec = 1; + if (target_pid == -1) { + attr->disabled = 1; + attr->enable_on_exec = 1; + } fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0); if (fd[0][counter] < 0 && verbose) @@ -251,9 +253,9 @@ static int run_perf_stat(int argc __used, const char **argv) unsigned long long t0, t1; int status = 0; int counter; - int pid = target_pid; + int pid; int child_ready_pipe[2], go_pipe[2]; - const bool forks = (target_pid == -1 && argc > 0); + const bool forks = (argc > 0); char buf; if (!system_wide) @@ -265,10 +267,10 @@ static int run_perf_stat(int argc __used, const char **argv) } if (forks) { - if ((pid = fork()) < 0) + if ((child_pid = fork()) < 0) perror("failed to fork"); - if (!pid) { + if (!child_pid) { close(child_ready_pipe[0]); close(go_pipe[1]); fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); @@ -297,8 +299,6 @@ static int run_perf_stat(int argc __used, const char **argv) exit(-1); } - child_pid = pid; - /* * Wait for the child to be ready to exec. */ @@ -309,6 +309,10 @@ static int run_perf_stat(int argc __used, const char **argv) close(child_ready_pipe[0]); } + if (target_pid == -1) + pid = child_pid; + else + pid = target_pid; for (counter = 0; counter < nr_counters; counter++) create_perf_stat_counter(counter, pid); @@ -321,7 +325,7 @@ static int run_perf_stat(int argc __used, const char **argv) close(go_pipe[1]); wait(&status); } else { - while(!done); + while(!done) sleep(1); } t1 = rdclock(); @@ -459,7 +463,7 @@ static volatile int signr = -1; static void skip_signal(int signo) { - if(target_pid != -1) + if(child_pid == -1) done = 1; signr = signo; -- 1.6.2.5