[PATCH v4 06/10] 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 | 45 +++++++++++++++++++++++++++++++++------
 1 file changed, 39 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 70b48a279b75..c06c2b701a15 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -439,6 +439,31 @@ static bool process_timeout(bool timeout, unsigned int 
interval, int *times)
                return print_interval(interval, times);
 }
 
+static bool process_evlist(struct evlist *evlist, unsigned int interval, int 
*times)
+{
+       bool stop = false;
+       enum evlist_ctl_cmd cmd = EVLIST_CTL_CMD_UNSUPPORTED;
+
+       if (evlist__ctlfd_process(evlist, &cmd) > 0) {
+               switch (cmd) {
+               case EVLIST_CTL_CMD_ENABLE:
+                       pr_info(EVLIST_ENABLED_MSG);
+                       stop = print_interval(interval, times);
+                       break;
+               case EVLIST_CTL_CMD_DISABLE:
+                       stop = print_interval(interval, times);
+                       pr_info(EVLIST_DISABLED_MSG);
+                       break;
+               case EVLIST_CTL_CMD_ACK:
+               case EVLIST_CTL_CMD_UNSUPPORTED:
+               default:
+                       break;
+               }
+       }
+
+       return stop;
+}
+
 static void enable_counters(void)
 {
        if (stat_config.initial_delay < 0) {
@@ -518,8 +543,8 @@ static int dispatch_events(pid_t pid, struct 
perf_stat_config *config)
 {
        pid_t child = 0;
        bool stop = false;
-       struct timespec time_to_sleep;
-       int sleep_time, status = 0;
+       int time_to_sleep, sleep_time, status = 0;
+       struct timespec time_start, time_stop, time_diff;
        int times = config->times;
 
        if (config->interval)
@@ -529,8 +554,7 @@ static int dispatch_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) {
@@ -543,8 +567,17 @@ static int dispatch_events(pid_t pid, struct 
perf_stat_config *config)
                if (child || stop || done)
                        break;
 
-               nanosleep(&time_to_sleep, NULL);
-               stop = process_timeout(config->timeout, config->interval, 
&times);
+               clock_gettime(CLOCK_MONOTONIC, &time_start);
+               if (!(evlist__poll(evsel_list, time_to_sleep) > 0)) { /* poll 
timeout or EINTR */
+                       stop = process_timeout(config->timeout, 
config->interval, &times);
+                       time_to_sleep = sleep_time;
+               } else { /* fd revent */
+                       stop = process_evlist(evsel_list, config->interval, 
&times);
+                       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);
 
        return status;
-- 
2.24.1