From 6d499a6b3d90277dbb7e408e7c70d68b507ef383 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 2 Aug 2022 12:10:04 -0700 Subject: [PATCH] perf lock: Print the number of lost entries for BPF Like the normal 'perf lock contention' output, it'd print the number of lost entries for BPF if exists or -v option is passed. Currently it uses BROKEN_CONTENDED stat for the lost count (due to full stack maps). $ sudo perf lock con -a -b --map-nr-entries 128 sleep 5 ... === output for debug=== bad: 43, total: 14903 bad rate: 0.29 % histogram of events caused bad sequence acquire: 0 acquired: 0 contended: 43 release: 0 Signed-off-by: Namhyung Kim Cc: Blake Jones Cc: Boqun Feng Cc: Davidlohr Bueso Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: Waiman Long Cc: Will Deacon Link: https://lore.kernel.org/r/20220802191004.347740-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-lock.c | 8 +++++++- tools/perf/util/bpf_lock_contention.c | 6 ++++-- tools/perf/util/bpf_skel/lock_contention.bpf.c | 9 +++++++-- tools/perf/util/lock-contention.h | 1 + 4 files changed, 19 insertions(+), 5 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index c6cc6c2964196..dd11d3471baf3 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -1472,8 +1472,11 @@ static void print_contention_result(void) pr_info(" %10s %s\n\n", "type", "caller"); bad = total = 0; + if (use_bpf) + bad = bad_hist[BROKEN_CONTENDED]; + while ((st = pop_from_result())) { - total++; + total += use_bpf ? st->nr_contended : 1; if (st->broken) bad++; @@ -1687,6 +1690,9 @@ static int __cmd_contention(int argc, const char **argv) lock_contention_stop(); lock_contention_read(&con); + + /* abuse bad hist stats for lost entries */ + bad_hist[BROKEN_CONTENDED] = con.lost; } else { err = perf_session__process_events(session); if (err) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index 0556cf4469ff7..c591a66733ef5 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -16,7 +16,7 @@ static struct lock_contention_bpf *skel; /* should be same as bpf_skel/lock_contention.bpf.c */ struct lock_contention_key { - u32 stack_id; + s32 stack_id; }; struct lock_contention_data { @@ -110,7 +110,7 @@ int lock_contention_stop(void) int lock_contention_read(struct lock_contention *con) { int fd, stack; - u32 prev_key, key; + s32 prev_key, key; struct lock_contention_data data; struct lock_stat *st; struct machine *machine = con->machine; @@ -119,6 +119,8 @@ int lock_contention_read(struct lock_contention *con) fd = bpf_map__fd(skel->maps.lock_stat); stack = bpf_map__fd(skel->maps.stacks); + con->lost = skel->bss->lost; + prev_key = 0; while (!bpf_map_get_next_key(fd, &prev_key, &key)) { struct map *kmap; diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index 67d46533e5181..9e8b94eb63204 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -12,7 +12,7 @@ #define MAX_ENTRIES 10240 struct contention_key { - __u32 stack_id; + __s32 stack_id; }; struct contention_data { @@ -27,7 +27,7 @@ struct tstamp_data { __u64 timestamp; __u64 lock; __u32 flags; - __u32 stack_id; + __s32 stack_id; }; /* callstack storage */ @@ -73,6 +73,9 @@ int enabled; int has_cpu; int has_task; +/* error stat */ +unsigned long lost; + static inline int can_record(void) { if (has_cpu) { @@ -116,6 +119,8 @@ int contention_begin(u64 *ctx) pelem->flags = (__u32)ctx[1]; pelem->stack_id = bpf_get_stackid(ctx, &stacks, BPF_F_FAST_STACK_CMP); + if (pelem->stack_id < 0) + lost++; return 0; } diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h index 8de8550f5ef89..2146efc33396e 100644 --- a/tools/perf/util/lock-contention.h +++ b/tools/perf/util/lock-contention.h @@ -113,6 +113,7 @@ struct lock_contention { struct machine *machine; struct hlist_head *result; unsigned long map_nr_entries; + unsigned long lost; }; #ifdef HAVE_BPF_SKEL -- 2.30.2