Commit 529772c4 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf lock contention: Support lock type filtering for BPF 



Likewise, add type_filter BPF hash map and check it when user gave a
lock type filter.

  $ sudo ./perf lock con -ab -Y rwlock -- ./perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  # 20 sender and receiver processes per group
  # 10 groups == 400 processes run

       Total time: 0.203 [sec]
   contended  total wait  max wait  avg wait       type  caller

          15   156.19 us  19.45 us  10.41 us   rwlock:W  do_exit+0x36d
           1    11.12 us  11.12 us  11.12 us   rwlock:R  do_wait+0x8b
           1     5.09 us   5.09 us   5.09 us   rwlock:W  release_task+0x6e

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20221219201732.460111-4-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent b4a7eff9

tools/perf/builtin-lock.c

+1 −0
Original line number Diff line number Diff line
@@ -1689,6 +1689,7 @@ static int __cmd_contention(int argc, const char **argv) 
		.map_nr_entries = bpf_map_entries,

		.max_stack = max_stack_depth,

		.stack_skip = stack_skip,

		.filters = &filters,

	};



	session = perf_session__new(use_bpf ? NULL : &data, &eops);

tools/perf/util/bpf_lock_contention.c

+14 −1
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ static struct lock_contention_bpf *skel; 
int lock_contention_prepare(struct lock_contention *con)

{

	int i, fd;

	int ncpus = 1, ntasks = 1;

	int ncpus = 1, ntasks = 1, ntypes = 1;

	struct evlist *evlist = con->evlist;

	struct target *target = con->target;
@@ -46,9 +46,12 @@ int lock_contention_prepare(struct lock_contention *con) 
		ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);

	if (target__has_task(target))

		ntasks = perf_thread_map__nr(evlist->core.threads);

	if (con->filters->nr_types)

		ntypes = con->filters->nr_types;



	bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);

	bpf_map__set_max_entries(skel->maps.task_filter, ntasks);

	bpf_map__set_max_entries(skel->maps.type_filter, ntypes);



	if (lock_contention_bpf__load(skel) < 0) {

		pr_err("Failed to load lock-contention BPF skeleton\n");
@@ -90,6 +93,16 @@ int lock_contention_prepare(struct lock_contention *con) 
		bpf_map_update_elem(fd, &pid, &val, BPF_ANY);

	}



	if (con->filters->nr_types) {

		u8 val = 1;



		skel->bss->has_type = 1;

		fd = bpf_map__fd(skel->maps.type_filter);



		for (i = 0; i < con->filters->nr_types; i++)

			bpf_map_update_elem(fd, &con->filters->types[i], &val, BPF_ANY);

	}



	/* these don't work well if in the rodata section */

	skel->bss->stack_skip = con->stack_skip;

	skel->bss->aggr_mode = con->aggr_mode;

tools/perf/util/bpf_skel/lock_contention.bpf.c

+19 −2
Original line number Diff line number Diff line
@@ -62,10 +62,18 @@ struct { 
	__uint(max_entries, 1);

} task_filter SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__uint(key_size, sizeof(__u32));

	__uint(value_size, sizeof(__u8));

	__uint(max_entries, 1);

} type_filter SEC(".maps");



/* control flags */

int enabled;

int has_cpu;

int has_task;

int has_type;

int stack_skip;



/* determine the key of lock stat */
@@ -74,7 +82,7 @@ int aggr_mode; 
/* error stat */

int lost;



static inline int can_record(void)

static inline int can_record(u64 *ctx)

{

	if (has_cpu) {

		__u32 cpu = bpf_get_smp_processor_id();
@@ -94,6 +102,15 @@ static inline int can_record(void) 
			return 0;

	}



	if (has_type) {

		__u8 *ok;

		__u32 flags = (__u32)ctx[1];



		ok = bpf_map_lookup_elem(&type_filter, &flags);

		if (!ok)

			return 0;

	}



	return 1;

}
@@ -116,7 +133,7 @@ int contention_begin(u64 *ctx) 
	__u32 pid;

	struct tstamp_data *pelem;



	if (!enabled || !can_record())

	if (!enabled || !can_record(ctx))

		return 0;



	pid = bpf_get_current_pid_tgid();

tools/perf/util/lock-contention.h

+1 −0
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ struct lock_contention { 
	struct target *target;

	struct machine *machine;

	struct hlist_head *result;

	struct lock_filter *filters;

	unsigned long map_nr_entries;

	int lost;

	int max_stack;