Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 22:21:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

perf stat: Enable counters when collecting process-wide or system-wide data

Browse Source 
Command 'perf stat' doesn't enable counters when collecting an
existing (by -p) process or system-wide statistics. Fix the
issue.

Change the condition of fork/exec subcommand. If there is a
subcommand parameter, perf always forks/execs 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 <yanmin_zhang@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sheng Yang <sheng@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jes Sorensen <Jes.Sorensen@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Zachary Amsden <zamsden@redhat.com>
Cc: <zhiteng.huang@intel.com>
LKML-Reference: <1268922965-14774-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Zhang, Yanmin 2010-03-18 11:36:03 -03:00 committed by Ingo Molnar
parent d6dc0b4ead
commit 6be2850eff
1 changed files with 14 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
tools/perf/builtin-stat.c
View File

@ -159,8 +159,10 @@ static void create_perf_stat_counter(int counter, int pid)
}
} else {
attr->inherit = inherit;
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;