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authorZhang, Yanmin <yanmin_zhang@linux.intel.com>2010-03-18 10:36:03 -0400
committerIngo Molnar <mingo@elte.hu>2010-03-18 11:21:11 -0400
commit6be2850effd6a8bae11d623c8c52e88d2fbc0e96 (patch)
treef8a2e34dc16a8e79e87b4c3fbe420c2346343cf1 /tools/perf/builtin-stat.c
parentd6dc0b4ead6e8720096ecfa3d9e899b47ddbc8ed (diff)
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>
Diffstat (limited to 'tools/perf/builtin-stat.c')
-rw-r--r--tools/perf/builtin-stat.c24
1 files changed, 14 insertions, 10 deletions
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 95db31cff6f..5f41244cbbf 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)
159 } 159 }
160 } else { 160 } else {
161 attr->inherit = inherit; 161 attr->inherit = inherit;
162 attr->disabled = 1; 162 if (target_pid == -1) {
163 attr->enable_on_exec = 1; 163 attr->disabled = 1;
164 attr->enable_on_exec = 1;
165 }
164 166
165 fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0); 167 fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0);
166 if (fd[0][counter] < 0 && verbose) 168 if (fd[0][counter] < 0 && verbose)
@@ -251,9 +253,9 @@ static int run_perf_stat(int argc __used, const char **argv)
251 unsigned long long t0, t1; 253 unsigned long long t0, t1;
252 int status = 0; 254 int status = 0;
253 int counter; 255 int counter;
254 int pid = target_pid; 256 int pid;
255 int child_ready_pipe[2], go_pipe[2]; 257 int child_ready_pipe[2], go_pipe[2];
256 const bool forks = (target_pid == -1 && argc > 0); 258 const bool forks = (argc > 0);
257 char buf; 259 char buf;
258 260
259 if (!system_wide) 261 if (!system_wide)
@@ -265,10 +267,10 @@ static int run_perf_stat(int argc __used, const char **argv)
265 } 267 }
266 268
267 if (forks) { 269 if (forks) {
268 if ((pid = fork()) < 0) 270 if ((child_pid = fork()) < 0)
269 perror("failed to fork"); 271 perror("failed to fork");
270 272
271 if (!pid) { 273 if (!child_pid) {
272 close(child_ready_pipe[0]); 274 close(child_ready_pipe[0]);
273 close(go_pipe[1]); 275 close(go_pipe[1]);
274 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); 276 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
@@ -297,8 +299,6 @@ static int run_perf_stat(int argc __used, const char **argv)
297 exit(-1); 299 exit(-1);
298 } 300 }
299 301
300 child_pid = pid;
301
302 /* 302 /*
303 * Wait for the child to be ready to exec. 303 * Wait for the child to be ready to exec.
304 */ 304 */
@@ -309,6 +309,10 @@ static int run_perf_stat(int argc __used, const char **argv)
309 close(child_ready_pipe[0]); 309 close(child_ready_pipe[0]);
310 } 310 }
311 311
312 if (target_pid == -1)
313 pid = child_pid;
314 else
315 pid = target_pid;
312 for (counter = 0; counter < nr_counters; counter++) 316 for (counter = 0; counter < nr_counters; counter++)
313 create_perf_stat_counter(counter, pid); 317 create_perf_stat_counter(counter, pid);
314 318
@@ -321,7 +325,7 @@ static int run_perf_stat(int argc __used, const char **argv)
321 close(go_pipe[1]); 325 close(go_pipe[1]);
322 wait(&status); 326 wait(&status);
323 } else { 327 } else {
324 while(!done); 328 while(!done) sleep(1);
325 } 329 }
326 330
327 t1 = rdclock(); 331 t1 = rdclock();
@@ -459,7 +463,7 @@ static volatile int signr = -1;
459 463
460static void skip_signal(int signo) 464static void skip_signal(int signo)
461{ 465{
462 if(target_pid != -1) 466 if(child_pid == -1)
463 done = 1; 467 done = 1;
464 468
465 signr = signo; 469 signr = signo;