From 954cdac74e1e7aca518c8ef49d4fa70c8ae72d7b Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Thu, 6 Apr 2023 14:06:08 -0700 Subject: [PATCH] perf lock contention: Add data failure stat It's possible to fail to update the data when the lock_stat map is full. We should check that case and show the number at the end. $ sudo ./perf lock con -ablv -E3 -- ./perf bench sched messaging ... contended total wait max wait avg wait address symbol 6157 208.48 ms 69.29 us 33.86 us ffff934c001c1f00 (spinlock) 4030 72.04 ms 61.84 us 17.88 us ffff934c000415c0 (spinlock) 3201 50.30 ms 47.73 us 15.71 us ffff934c2eead850 (spinlock) === output for debug === bad: 0, total: 13388 bad rate: 0.00 % histogram of failure reasons task: 0 stack: 0 time: 0 data: 0 <----- added Signed-off-by: Namhyung Kim Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Hao Luo Cc: Ingo Molnar Cc: Jiri Olsa Cc: Juri Lelli Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20230406210611.1622492-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-lock.c | 4 +++- tools/perf/util/bpf_lock_contention.c | 1 + tools/perf/util/bpf_skel/lock_contention.bpf.c | 4 +++- tools/perf/util/lock-contention.h | 1 + 4 files changed, 8 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index 9b92c7a5aefb5..01b318d6c80a3 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -1626,7 +1626,7 @@ static void sort_contention_result(void) static void print_bpf_events(int total, struct lock_contention_fails *fails) { /* Output for debug, this have to be removed */ - int broken = fails->task + fails->stack + fails->time; + int broken = fails->task + fails->stack + fails->time + fails->data; if (quiet || total == 0 || (broken == 0 && verbose <= 0)) return; @@ -1640,7 +1640,9 @@ static void print_bpf_events(int total, struct lock_contention_fails *fails) pr_info(" %10s: %d\n", "task", fails->task); pr_info(" %10s: %d\n", "stack", fails->stack); pr_info(" %10s: %d\n", "time", fails->time); + pr_info(" %10s: %d\n", "data", fails->data); } + static void print_contention_result(struct lock_contention *con) { struct lock_stat *st; diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index 8a5d0eb441898..0071058ac3d2b 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -262,6 +262,7 @@ int lock_contention_read(struct lock_contention *con) con->fails.task = skel->bss->task_fail; con->fails.stack = skel->bss->stack_fail; con->fails.time = skel->bss->time_fail; + con->fails.data = skel->bss->data_fail; stack_trace = zalloc(stack_size); if (stack_trace == NULL) diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index f9d2d792ccc83..cb87c98e53408 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -124,6 +124,7 @@ int aggr_mode; int task_fail; int stack_fail; int time_fail; +int data_fail; static inline int can_record(u64 *ctx) { @@ -380,7 +381,8 @@ int contention_end(u64 *ctx) if (aggr_mode == LOCK_AGGR_ADDR) first.flags |= check_lock_type(pelem->lock, pelem->flags); - bpf_map_update_elem(&lock_stat, &key, &first, BPF_NOEXIST); + if (bpf_map_update_elem(&lock_stat, &key, &first, BPF_NOEXIST) < 0) + __sync_fetch_and_add(&data_fail, 1); bpf_map_delete_elem(&tstamp, &pid); return 0; } diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h index 10c28302420ce..3ed1cad370fca 100644 --- a/tools/perf/util/lock-contention.h +++ b/tools/perf/util/lock-contention.h @@ -126,6 +126,7 @@ struct lock_contention_fails { int task; int stack; int time; + int data; }; struct lock_contention { -- 2.30.2