perf stat: Enable counters when collecting process-wide or system-wide data
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:
parent
d6dc0b4ead
commit
6be2850eff
|
@ -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;
|
||||
|
|
Loading…
Reference in New Issue