Messages in this thread Patch in this message | | | Date | Mon, 6 Jul 2020 21:34:18 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v9 11/15] perf stat: implement control commands handling |
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On Mon, Jul 06, 2020 at 05:47:54PM +0300, Alexey Budankov wrote: > > On 06.07.2020 15:34, Jiri Olsa wrote: > > On Fri, Jul 03, 2020 at 10:47:22AM +0300, Alexey Budankov wrote: > >> > >> Implement handling of 'enable' and 'disable' control commands > >> coming from control file descriptor. process_evlist() function > >> checks for events on control fds and makes required operations. > >> If poll event splits initiated timeout interval then the reminder > >> is calculated and still waited in the following poll() syscall. > >> > >> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> > >> --- > >> tools/perf/builtin-stat.c | 75 ++++++++++++++++++++++++++++----------- > >> 1 file changed, 55 insertions(+), 20 deletions(-) > >> > >> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > >> index 9e4288ecf2b8..5021f7286422 100644 > >> --- a/tools/perf/builtin-stat.c > >> +++ b/tools/perf/builtin-stat.c > >> @@ -485,6 +485,31 @@ static bool handle_interval(unsigned int interval, int *times) > >> return false; > >> } > >> > >> +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 = handle_interval(interval, times); > >> + break; > >> + case EVLIST_CTL_CMD_DISABLE: > >> + stop = handle_interval(interval, times); > > > > I still don't understand why you call handle_interval in here > > > > I don't see it being necessary.. you enable events and handle_interval, > > wil be called in the next iteration of dispatch_events, why complicate > > this function with that? > > Printing event counts at the moment of command processing lets scripts > built on top of stat output to provide more plain and accurate metrics. > Otherwise it may get spikes in the beginning of the next time interval > because not all counts lay inside [Events enabled, Events disable] > If -I interval is large tail event count can be also large. Compare the > output below with the output in the cover letter. Either way is possible > but the latter one likely complicates the scripts I mentioned above. > > perf=tools/perf/perf > ${perf} stat -D -1 -e cpu-cycles -a -I 1000 \ > --control fd:${ctl_fd},${ctl_fd_ack} \ > -- sleep 40 & > > Events disabled > # time counts unit events > 1.001100723 <not counted> cpu-cycles > 2.003146566 <not counted> cpu-cycles > 3.005073317 <not counted> cpu-cycles > 4.006337062 <not counted> cpu-cycles > Events enabled > enable acked(ack) > 5.011182000 54,128,692 cpu-cycles <=== > 6.012300167 3,648,804,827 cpu-cycles > 7.013631689 590,438,536 cpu-cycles > 8.015558583 406,935,663 cpu-cycles > 9.017455505 407,806,862 cpu-cycles > 10.019300780 399,351,824 cpu-cycles > 11.021180025 404,584,417 cpu-cycles > 12.023033661 537,787,981 cpu-cycles > 13.024422354 699,395,364 cpu-cycles > 14.026325749 397,871,324 cpu-cycles > disable acked() > Events disabled > 15.027857981 396,956,159 cpu-cycles <=== > 16.029279264 <not counted> cpu-cycles > 17.031131311 <not counted> cpu-cycles > 18.033010580 <not counted> cpu-cycles > 19.034918883 <not counted> cpu-cycles > enable acked(ack) > Events enabled > 20.036758793 183,544,975 cpu-cycles <=== > 21.038163289 419,054,544 cpu-cycles > 22.040108245 413,993,309 cpu-cycles > 23.042042365 403,584,493 cpu-cycles > 24.043985381 416,512,094 cpu-cycles > 25.045925682 401,513,429 cpu-cycles > # time counts unit events > 26.047822238 461,205,096 cpu-cycles > 27.049784263 414,319,162 cpu-cycles > 28.051745360 403,706,915 cpu-cycles > 29.053674600 416,502,883 cpu-cycles > disable acked() > Events disabled > 30.054750685 414,184,409 cpu-cycles <===
ok, but we could still take handle_interval out of process_evlist and the interval process will be more clear for me (with some additional comments in the code) ... perhaps something like below?
thanks, jirka
--- diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 5021f7286422..af83bf6b2db0 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -485,19 +485,18 @@ static bool handle_interval(unsigned int interval, int *times) return false; } -static bool process_evlist(struct evlist *evlist, unsigned int interval, int *times) +static bool process_evlist(struct evlist *evlist) { - bool stop = false; enum evlist_ctl_cmd cmd = EVLIST_CTL_CMD_UNSUPPORTED; + bool enabled = false; if (evlist__ctlfd_process(evlist, &cmd) > 0) { switch (cmd) { case EVLIST_CTL_CMD_ENABLE: pr_info(EVLIST_ENABLED_MSG); - stop = handle_interval(interval, times); + enabled = true; break; case EVLIST_CTL_CMD_DISABLE: - stop = handle_interval(interval, times); pr_info(EVLIST_DISABLED_MSG); break; case EVLIST_CTL_CMD_ACK: @@ -507,7 +506,7 @@ static bool process_evlist(struct evlist *evlist, unsigned int interval, int *ti } } - return stop; + return enabled; } static void enable_counters(void) @@ -618,7 +617,8 @@ static int dispatch_events(bool forks, int timeout, int interval, int *times) stop = handle_interval(interval, times); time_to_sleep = sleep_time; } else { /* fd revent */ - stop = process_evlist(evsel_list, interval, times); + if (process_evlist(evsel_list)) + stop = handle_interval(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 +
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