[PATCH v3 5/9] perf stat: implement control commands handling

[Alexey Budankov]

Implement handling of 'enable' and 'disable' control commands
coming from control file descriptor.

Signed-off-by: Alexey Budankov <alexey.budan...@linux.intel.com>
---
 tools/perf/builtin-stat.c | 48 +++++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 12 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 73404b723592..abea82a1ba24 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -460,8 +460,9 @@ static int handle_events(pid_t pid, struct perf_stat_config 
*config)
 {
        pid_t child = 0;
        bool res, stop = false;
-       struct timespec time_to_sleep;
-       int sleep_time, status = 0, times = config->times;
+       int time_to_sleep, sleep_time, status = 0, times = config->times;
+       enum evlist_ctl_cmd cmd = EVLIST_CTL_CMD_UNSUPPORTED;
+       struct timespec time_start, time_stop, time_diff;
 
        if (config->interval)
                sleep_time = config->interval;
@@ -470,22 +471,45 @@ static int handle_events(pid_t pid, struct 
perf_stat_config *config)
        else
                sleep_time = 1000;
 
-       time_to_sleep.tv_sec  = sleep_time / MSEC_PER_SEC;
-       time_to_sleep.tv_nsec = (sleep_time % MSEC_PER_SEC) * NSEC_PER_MSEC;
+       time_to_sleep = sleep_time;
 
        do {
                if (pid != -1)
                        child = waitpid(pid, &status, WNOHANG);
                if (child || stop || done)
                        break;
-               nanosleep(&time_to_sleep, NULL);
-               if (pid == -1)
-                       stop = !is_target_alive(&target, 
evsel_list->core.threads);
-               if (config->timeout) {
-                       stop = !stop ? true : stop;
-               } else {
-                       res = print_interval_and_stop(config, &times);
-                       stop = !stop ? res : stop;
+               clock_gettime(CLOCK_MONOTONIC, &time_start);
+               if (!(evlist__poll(evsel_list, time_to_sleep) > 0)) { /* poll 
timeout or EINTR */
+                       if (pid == -1)
+                               stop = !is_target_alive(&target, 
evsel_list->core.threads);
+                       if (config->timeout) {
+                               stop = !stop ? true : stop;
+                       } else {
+                               res = print_interval_and_stop(config, &times);
+                               stop = !stop ? res : stop;
+                       }
+                       time_to_sleep = sleep_time;
+               } else { /* fd revent */
+                       if (evlist__ctlfd_process(evsel_list, &cmd) > 0) {
+                               switch (cmd) {
+                               case EVLIST_CTL_CMD_ENABLE:
+                                       pr_info(EVLIST_ENABLED_MSG);
+                                       stop = print_interval_and_stop(config, 
&times);
+                                       break;
+                               case EVLIST_CTL_CMD_DISABLE:
+                                       stop = print_interval_and_stop(config, 
&times);
+                                       pr_info(EVLIST_DISABLED_MSG);
+                                       break;
+                               case EVLIST_CTL_CMD_ACK:
+                               case EVLIST_CTL_CMD_UNSUPPORTED:
+                               default:
+                                       break;
+                               }
+                       }
+                       clock_gettime(CLOCK_MONOTONIC, &time_stop);
+                       diff_timespec(&time_diff, &time_stop, &time_start);
+                       time_to_sleep -= time_diff.tv_sec * MSEC_PER_SEC +
+                                        time_diff.tv_nsec / NSEC_PER_MSEC;
                }
        } while (1);
 
-- 
2.24.1