From 35bf007e2ee0447166081646c0797bfa831b062f Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Mon, 27 Mar 2023 15:57:10 -0700 Subject: [PATCH] perf lock contention: Fix debug stat if no contention It should not divide if the total number is 0. Otherwise it'd show NaN in the bad rate output. Also add a whitespace in the "output for debug" message. $ sudo perf lock contention -abv true Looking at the vmlinux_path (8 entries long) symsrc__init: cannot get elf header. Using /proc/kcore for kernel data Using /proc/kallsyms for symbols contended total wait max wait avg wait type caller === output for debug=== bad: 0, total: 0 bad rate: -nan % <------------------------- (here) histogram of events caused bad sequence acquire: 0 acquired: 0 contended: 0 release: 0 Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Hao Luo Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20230327225711.245738-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-lock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index 3c8a19e..82dd2df 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -1323,10 +1323,10 @@ static void print_bad_events(int bad, int total) for (i = 0; i < BROKEN_MAX; i++) broken += bad_hist[i]; - if (quiet || (broken == 0 && verbose <= 0)) + if (quiet || total == 0 || (broken == 0 && verbose <= 0)) return; - pr_info("\n=== output for debug===\n\n"); + pr_info("\n=== output for debug ===\n\n"); pr_info("bad: %d, total: %d\n", bad, total); pr_info("bad rate: %.2f %%\n", (double)bad / (double)total * 100); pr_info("histogram of events caused bad sequence\n"); -- 2.7.4