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Date:   Wed, 21 Apr 2021 12:18:23 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Song Liu <songliubraving@fb.com>
Cc:     Song Liu <song@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Kernel Team <Kernel-team@fb.com>,
        "acme@kernel.org" <acme@kernel.org>,
        "acme@redhat.com" <acme@redhat.com>,
        "namhyung@kernel.org" <namhyung@kernel.org>,
        "jolsa@kernel.org" <jolsa@kernel.org>
Subject: Re: [PATCH v4 3/4] perf-stat: introduce config
 stat.bpf-counter-events
Message-ID: <YH/773ecFa3iESlH@krava>
References: <20210419203649.164121-1-song@kernel.org>
 <20210419203649.164121-4-song@kernel.org>
 <YH8P5ol5JRr5JO5v@krava>
 <EE06CC67-3FFA-43E2-B032-EC8B37A9EC1C@fb.com>
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On Tue, Apr 20, 2021 at 09:21:32PM +0000, Song Liu wrote:
> 
> 
> > On Apr 20, 2021, at 10:31 AM, Jiri Olsa <jolsa@redhat.com> 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. 

ah it's different file :) then it's better as it is, sorry

jirka

> 
> Thanks,
> Song
>