Re: [PATCH v4 3/4] perf-stat: introduce config stat.bpf-counter-events

[Song Liu]

> On Apr 20, 2021, at 10:31 AM, Jiri Olsa  wrote:
> 
> On Mon, Apr 19, 2021 at 01:36:48PM -0700, Song Liu wrote:
> 
> SNIP
> 
>>  if (stat_config.initial_delay < 0) {
>> @@ -784,11 +790,11 @@ static int __run_perf_stat(int argc, const char 
>> **argv, int run_idx)
>>  if (affinity__setup(&affinity) < 0)
>>  return -1;
>> 
>> -if (target__has_bpf(&target)) {
>> -evlist__for_each_entry(evsel_list, counter) {
>> -if (bpf_counter__load(counter, &target))
>> -return -1;
>> -}
>> +evlist__for_each_entry(evsel_list, counter) {
>> +if (bpf_counter__load(counter, &target))
>> +return -1;
>> +if (!evsel__is_bpf(counter))
>> +all_counters_use_bpf = false;
> 
> could be done in bpf_counter__load, check below:
> 
>>  }
>> 
>>  evlist__for_each_cpu (evsel_list, i, cpu) {
>> diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
>> index 5de991ab46af9..33b1888103dfa 100644
>> --- a/tools/perf/util/bpf_counter.c
>> +++ b/tools/perf/util/bpf_counter.c
>> @@ -790,7 +790,8 @@ int bpf_counter__load(struct evsel *evsel, struct target 
>> *target)
>> {
>>  if (target->bpf_str)
>>  evsel->bpf_counter_ops = &bpf_program_profiler_ops;
>> -else if (target->use_bpf)
>> +else if (target->use_bpf ||
>> + evsel__match_bpf_counter_events(evsel->name))
>>  evsel->bpf_counter_ops = &bperf_ops;
> 
> with:
>   else
>   all_counters_use_bpf = false;
> 
> I was also thinking of oving it to evlist, but it's sat specific,
> so I think it's good as static.. thanks for changing the implementation

Hmm... then we need to somehow make all_counters_use_bpf visible in
bpf_counter.c, which won't be very clean. Also, since this is stat 
specific, I guess it is better to keep it inside builtin-stat.c?
The runtime overhead should be minimal. 

Thanks,
Song

Re: [PATCH v4 3/4] perf-stat: introduce config stat.bpf-counter-events

[Jiri Olsa]

On Mon, Apr 19, 2021 at 01:36:48PM -0700, Song Liu wrote:

SNIP

>   if (stat_config.initial_delay < 0) {
> @@ -784,11 +790,11 @@ static int __run_perf_stat(int argc, const char **argv, 
> int run_idx)
>   if (affinity__setup(&affinity) < 0)
>   return -1;
>  
> - if (target__has_bpf(&target)) {
> - evlist__for_each_entry(evsel_list, counter) {
> - if (bpf_counter__load(counter, &target))
> - return -1;
> - }
> + evlist__for_each_entry(evsel_list, counter) {
> + if (bpf_counter__load(counter, &target))
> + return -1;
> + if (!evsel__is_bpf(counter))
> + all_counters_use_bpf = false;

could be done in bpf_counter__load, check below:

>   }
>  
>   evlist__for_each_cpu (evsel_list, i, cpu) {
> diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c
> index 5de991ab46af9..33b1888103dfa 100644
> --- a/tools/perf/util/bpf_counter.c
> +++ b/tools/perf/util/bpf_counter.c
> @@ -790,7 +790,8 @@ int bpf_counter__load(struct evsel *evsel, struct target 
> *target)
>  {
>   if (target->bpf_str)
>   evsel->bpf_counter_ops = &bpf_program_profiler_ops;
> - else if (target->use_bpf)
> + else if (target->use_bpf ||
> +  evsel__match_bpf_counter_events(evsel->name))
>   evsel->bpf_counter_ops = &bperf_ops;

with:
else
all_counters_use_bpf = false;

I was also thinking of oving it to evlist, but it's sat specific,
so I think it's good as static.. thanks for changing the implementation

jirka

>  
>   if (evsel->bpf_counter_ops)
> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> index 6bcb5ef221f8c..63d472b336de2 100644
> --- a/tools/perf/util/config.c
> +++ b/tools/perf/util/config.c
> @@ -18,6 +18,7 @@
>  #include "util/hist.h"  /* perf_hist_config */
>  #include "util/llvm-utils.h"   /* perf_llvm_config */
>  #include "util/stat.h"  /* perf_stat__set_big_num */
> +#include "util/evsel.h"  /* evsel__hw_names, evsel__use_bpf_counters */
>  #include "build-id.h"
>  #include "debug.h"
>  #include "config.h"
> @@ -460,6 +461,9 @@ static int perf_stat_config(const char *var, const char 
> *value)
>   if (!strcmp(var, "stat.no-csv-summary"))
>   perf_stat__set_no_csv_summary(perf_config_bool(var, value));
>  
> + if (!strcmp(var, "stat.bpf-counter-events"))
> + evsel__bpf_counter_events = strdup(value);
> +
>   /* Add other config variables here. */
>   return 0;
>  }

SNIP