On Wed, Sep 25, 2024 at 01:55:22PM +0000, Tengda Wu wrote: > bperf restricts the size of perf_attr_map's entries to 16, which > cannot hold all events in many scenarios. A typical example is > when the user specifies `-a -ddd` ([0]). And in other cases such as > top-down analysis, which often requires a set of more than 16 PMUs > to be collected simultaneously. > > Fix this by increase perf_attr_map entries to 100, and an event > number check has been introduced when bperf__load() to ensure that > users receive a more friendly prompt when the event limit is reached. > > [0] https://lore.kernel.org/all/20230104064402.1551516-3-namhyung@xxxxxxxxxx/ Apparently this patch was never applied. I don't know how much you need but having too many events at the same time won't be very useful because multiplexing could reduce the accuracy. Thanks, Namhyung > > Fixes: 7fac83aaf2ee ("perf stat: Introduce 'bperf' to share hardware PMCs with BPF") > Signed-off-by: Tengda Wu <wutengda@xxxxxxxxxxxxxxx> > --- > tools/perf/util/bpf_counter.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/bpf_counter.c b/tools/perf/util/bpf_counter.c > index 7a8af60e0f51..3346129c20cf 100644 > --- a/tools/perf/util/bpf_counter.c > +++ b/tools/perf/util/bpf_counter.c > @@ -28,7 +28,7 @@ > #include "bpf_skel/bperf_leader.skel.h" > #include "bpf_skel/bperf_follower.skel.h" > > -#define ATTR_MAP_SIZE 16 > +#define ATTR_MAP_SIZE 100 > > static inline void *u64_to_ptr(__u64 ptr) > { > @@ -451,6 +451,12 @@ static int bperf__load(struct evsel *evsel, struct target *target) > enum bperf_filter_type filter_type; > __u32 filter_entry_cnt, i; > > + if (evsel->evlist->core.nr_entries > ATTR_MAP_SIZE) { > + pr_err("Too many events, please limit to %d or less\n", > + ATTR_MAP_SIZE); > + return -1; > + } > + > if (bperf_check_target(evsel, target, &filter_type, &filter_entry_cnt)) > return -1; > > -- > 2.34.1 >
