From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <6f83991b-e4d6-b573-9e1c-074f2c612ff7@linux.intel.com> Date: Wed, 15 Mar 2023 09:20:49 +0000 MIME-Version: 1.0 Content-Language: en-US To: Umesh Nerlige Ramappa References: <20230314121740.1195358-1-tvrtko.ursulin@linux.intel.com> From: Tvrtko Ursulin In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [igt-dev] [Intel-gfx] [PATCH i-g-t] intel_gpu_top: Use actual period when calculating client busyness List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: igt-dev@lists.freedesktop.org, Intel-gfx@lists.freedesktop.org Errors-To: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" List-ID: Hi Umesh, On 14/03/2023 18:25, Umesh Nerlige Ramappa wrote: > lgtm, > > Reviewed-by: Umesh Nerlige Ramappa Thanks - I had one second thought though. See below please. > On Tue, Mar 14, 2023 at 12:17:40PM +0000, Tvrtko Ursulin wrote: >> From: Tvrtko Ursulin >> >> On a slow machine, or with many processes and/or file descriptors to >> parse, the period of the scanning loop can drift significantly from the >> assumed value. This results in artificially inflated client busyness >> percentages. >> >> To alleviate the issue take some real timestamps and use actual elapsed >> time when calculating relative busyness. >> >> Signed-off-by: Tvrtko Ursulin >> --- >> tools/intel_gpu_top.c | 39 ++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 38 insertions(+), 1 deletion(-) >> >> diff --git a/tools/intel_gpu_top.c b/tools/intel_gpu_top.c >> index e13e35b71f4b..af4b350da8e4 100644 >> --- a/tools/intel_gpu_top.c >> +++ b/tools/intel_gpu_top.c >> @@ -43,6 +43,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #include "igt_perf.h" >> @@ -2524,6 +2525,38 @@ static void show_help_screen(void) >> "\n"); >> } >> >> +static int gettime(struct timespec *ts) >> +{ >> +    memset(ts, 0, sizeof(*ts)); >> + >> +#ifdef CLOCK_MONOTONIC_RAW >> +    if (!clock_gettime(CLOCK_MONOTONIC_RAW, ts)) >> +        return 0; >> +#endif >> +#ifdef CLOCK_MONOTONIC_COARSE >> +    if (!clock_gettime(CLOCK_MONOTONIC_COARSE, ts)) >> +        return 0; >> +#endif So I copied this (with some edits) from igt_core.c but I think I should actually remove the CLOCK_MONOTONIC_COARSE option. The usage in intel_gpu_top is not performance sensitive and tick granularity actually defeats to point of this patch. Okay to keep the r-b if I remove it? Regards, Tvrtko >> + >> +    return clock_gettime(CLOCK_MONOTONIC, ts); >> +} >> + >> +static unsigned long elapsed_us(struct timespec *prev, unsigned int >> period_us) >> +{ >> +    unsigned long elapsed; >> +    struct timespec now; >> + >> +    if (gettime(&now)) >> +        return period_us; >> + >> +    elapsed = ((now.tv_nsec - prev->tv_nsec) / 1000 + >> +               (unsigned long)USEC_PER_SEC * (now.tv_sec - >> prev->tv_sec)); >> + >> +    *prev = now; >> + >> +    return elapsed; >> +} >> + >> int main(int argc, char **argv) >> { >>     unsigned int period_us = DEFAULT_PERIOD_MS * 1000; >> @@ -2537,6 +2570,7 @@ int main(int argc, char **argv) >>     char *pmu_device, *opt_device = NULL; >>     struct igt_device_card card; >>     char *codename = NULL; >> +    struct timespec ts; >> >>     /* Parse options */ >>     while ((ch = getopt(argc, argv, "o:s:d:pcJLlh")) != -1) { >> @@ -2690,6 +2724,7 @@ int main(int argc, char **argv) >> >>     pmu_sample(engines); >>     scan_clients(clients, false); >> +    gettime(&ts); >>     codename = igt_device_get_pretty_name(&card, false); >> >>     if (output_mode == JSON) >> @@ -2698,6 +2733,7 @@ int main(int argc, char **argv) >>     while (!stop_top) { >>         struct clients *disp_clients; >>         bool consumed = false; >> +        unsigned int scan_us; >>         int j, lines = 0; >>         struct winsize ws; >>         struct client *c; >> @@ -2720,6 +2756,7 @@ int main(int argc, char **argv) >>         t = (double)(engines->ts.cur - engines->ts.prev) / 1e9; >> >>         disp_clients = scan_clients(clients, true); >> +        scan_us = elapsed_us(&ts, period_us); >> >>         if (stop_top) >>             break; >> @@ -2757,7 +2794,7 @@ int main(int argc, char **argv) >> >>                     lines = print_client(c, engines, t, >>                                  lines, con_w, >> -                                 con_h, period_us, >> +                                 con_h, scan_us, >>                                  &class_w); >>                 } >> >> -- >> 2.37.2 >>