Re: [PATCH v2 2/4] perf stat: add rusage utime and stime events

[Xing Zhengjun <zhengjun.xing@linux.intel.com>]

On 4/6/2022 3:28 PM, Florian Fischer wrote:
> It bothered me that during benchmarking using perf stat (to collect
> for example CPU cache events) I could not simultaneously retrieve the
> times spend in user or kernel mode in a machine readable format.
> 
> When running perf stat the output for humans contains the times
> reported by rusage and wait4.
> 
> $ perf stat -e cache-misses:u -- true
> 
>   Performance counter stats for 'true':
> 
>               4,206      cache-misses:u
> 
>         0.001113619 seconds time elapsed
> 
>         0.001175000 seconds user
>         0.000000000 seconds sys
> 
> But perf stat's machine-readable format does not provide this information.
> 
> $ perf stat -x, -e cache-misses:u -- true
> 4282,,cache-misses:u,492859,100.00,,
> 
> I found no way to retrieve this information using the available events
> while using machine-readable output.
> 
> This patch adds two new tool internal events 'rusage_user_time'
> and 'rusage_system_time' as well as their aliases 'ru_utime' and
> 'ru_stime', similarly to the already present 'duration_time' event.
> 
> Both events use the already collected rusage information obtained by wait4
> and tracked in the global ru_stats.
> 
> Examples presenting cache-misses and rusage information in both human and
> machine-readable form:
> 
> $ ./perf stat -e duration_time,ru_utime,ru_stime,cache-misses -- grep -q -r duration_time .
> 
>   Performance counter stats for 'grep -q -r duration_time .':
> 
>          67,422,542 ns   duration_time:u
>              50,517 us   ru_utime:u
>              16,839 us   ru_stime:u
>              30,937      cache-misses:u

Duration_time unit is "ns", while "ru_utime" and "ru_stime" unit is 
"us",  I think they should use the same time unit.

> 
>         0.067422542 seconds time elapsed
> 
>         0.050517000 seconds user
>         0.016839000 seconds sys
> 
> $ ./perf stat -x, -e duration_time,ru_utime,ru_stime,cache-misses -- grep -q -r duration_time .
> 72134524,ns,duration_time:u,72134524,100.00,,
> 65225,us,ru_utime:u,65225,100.00,,
> 6865,us,ru_stime:u,6865,100.00,,
> 38705,,cache-misses:u,71189328,100.00,,
> 
> Signed-off-by: Florian Fischer <florian.fischer@muhq.space>
> ---
>   tools/perf/builtin-stat.c      | 36 ++++++++++++++++++++++++++--------
>   tools/perf/util/evsel.h        |  3 +++
>   tools/perf/util/parse-events.l |  2 ++
>   3 files changed, 33 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 61faffb535f5..c73afc8f6da5 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -342,15 +342,35 @@ static int evsel__write_stat_event(struct evsel *counter, int cpu_map_idx, u32 t
>   static int read_single_counter(struct evsel *counter, int cpu_map_idx,
>   			       int thread, struct timespec *rs)
>   {
> -	if (counter->tool_event == PERF_TOOL_DURATION_TIME) {
> -		u64 val = rs->tv_nsec + rs->tv_sec*1000000000ULL;
> -		struct perf_counts_values *count =
> -			perf_counts(counter->counts, cpu_map_idx, thread);
> -		count->ena = count->run = val;
> -		count->val = val;
> -		return 0;
> +	switch(counter->tool_event) {
> +		case PERF_TOOL_DURATION_TIME: {
> +			u64 val = rs->tv_nsec + rs->tv_sec*1000000000ULL;
> +			struct perf_counts_values *count =
> +				perf_counts(counter->counts, cpu_map_idx, thread);
> +			count->ena = count->run = val;
> +			count->val = val;
> +			return 0;
> +		}
> +		case PERF_TOOL_RU_UTIME:
> +		case PERF_TOOL_RU_STIME: {
> +			u64 val;
> +			struct perf_counts_values *count =
> +				perf_counts(counter->counts, cpu_map_idx, thread);
> +			if (counter->tool_event == PERF_TOOL_RU_UTIME)
> +				val = ru_stats.ru_utime_usec_stat.mean;
> +			else
> +				val = ru_stats.ru_stime_usec_stat.mean;
> +			count->ena = count->run = val;
> +			count->val = val;
> +			return 0;
> +		}
> +		default:
> +		case PERF_TOOL_NONE:
> +			return evsel__read_counter(counter, cpu_map_idx, thread);
> +		case PERF_TOOL_LAST:
> +			/* this case should never be reached */
> +			return 0;
>   	}
> -	return evsel__read_counter(counter, cpu_map_idx, thread);
>   }
>   
>   /*
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index 041b42d33bf5..e89b1224ae61 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -30,6 +30,9 @@ typedef int (evsel__sb_cb_t)(union perf_event *event, void *data);
>   enum perf_tool_event {
>   	PERF_TOOL_NONE		= 0,
>   	PERF_TOOL_DURATION_TIME = 1,
> +	PERF_TOOL_RU_UTIME = 2,
> +	PERF_TOOL_RU_STIME = 3,
> +	PERF_TOOL_LAST
>   };
>   
>   /** struct evsel - event selector
> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> index 5b6e4b5249cf..3c7227b8035c 100644
> --- a/tools/perf/util/parse-events.l
> +++ b/tools/perf/util/parse-events.l
> @@ -353,6 +353,8 @@ alignment-faults				{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_AL
>   emulation-faults				{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EMULATION_FAULTS); }
>   dummy						{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); }
>   duration_time					{ return tool(yyscanner, PERF_TOOL_DURATION_TIME); }
> +rusage_user_time|ru_utime	{ return tool(yyscanner, PERF_TOOL_RU_UTIME); }
> +rusage_system_time|ru_stime	{ return tool(yyscanner, PERF_TOOL_RU_STIME); }
>   bpf-output					{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); }
>   cgroup-switches					{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CGROUP_SWITCHES); }
>   

-- 
Zhengjun Xing