From: Gabriele Monaco Date: Fri, 7 Feb 2025 08:04:45 +0000 (+0100) Subject: perf ftrace latency: allow to hide empty buckets X-Git-Tag: block-6.15-20250403~13^2~147 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=833d025239491767d9009c956de03c14f9bbd990;p=linux-block.git perf ftrace latency: allow to hide empty buckets Especially while using several buckets, it isn't uncommon to have some of them empty and reading the histogram may be a bit more complex: # perf ftrace latency -a -T mutex_lock --bucket-range 5 --max-latency 200 # DURATION | COUNT | GRAPH | 0 - 5 us | 14816 | ###################################### | 5 - 10 us | 1228 | ### | 10 - 15 us | 438 | # | 15 - 20 us | 106 | | 20 - 25 us | 21 | | 25 - 30 us | 11 | | 30 - 35 us | 1 | | 35 - 40 us | 2 | | 40 - 45 us | 4 | | 45 - 50 us | 0 | | 50 - 55 us | 1 | | 55 - 60 us | 0 | | 60 - 65 us | 1 | | 65 - 70 us | 1 | | 70 - 75 us | 1 | | 75 - 80 us | 2 | | 80 - 85 us | 0 | | 85 - 90 us | 1 | | 90 - 95 us | 0 | | 95 - 100 us | 1 | | 100 - 105 us | 0 | | 105 - 110 us | 0 | | 110 - 115 us | 0 | | 115 - 120 us | 0 | | 120 - 125 us | 1 | | 125 - 130 us | 0 | | 130 - 135 us | 0 | | 135 - 140 us | 1 | | 140 - 145 us | 0 | | 145 - 150 us | 0 | | 150 - 155 us | 0 | | 155 - 160 us | 0 | | 160 - 165 us | 0 | | 165 - 170 us | 0 | | 170 - 175 us | 0 | | 175 - 180 us | 0 | | 180 - 185 us | 0 | | 185 - 190 us | 0 | | 190 - 195 us | 0 | | 195 - 200 us | 0 | | 200 - ... us | 2 | | Allow the optional flag --hide-empty to remove buckets with no element and produce a more compact graph. This feature could be misleading since there is no clear indication for missing buckets, for this reason it's disabled by default. # perf ftrace latency -a -T mutex_lock --bucket-range 5 --max-latency --hide-empty 200 # DURATION | COUNT | GRAPH | 0 - 5 us | 14816 | ###################################### | 5 - 10 us | 1228 | ### | 10 - 15 us | 438 | # | 15 - 20 us | 106 | | 20 - 25 us | 21 | | 25 - 30 us | 11 | | 30 - 35 us | 1 | | 35 - 40 us | 2 | | 40 - 45 us | 4 | | 50 - 55 us | 1 | | 60 - 65 us | 1 | | 65 - 70 us | 1 | | 70 - 75 us | 1 | | 75 - 80 us | 2 | | 85 - 90 us | 1 | | 95 - 100 us | 1 | | 120 - 125 us | 1 | | 135 - 140 us | 1 | | 200 - ... us | 2 | | Signed-off-by: Gabriele Monaco Link: https://lore.kernel.org/r/20250207080446.77630-2-gmonaco@redhat.com Signed-off-by: Namhyung Kim --- diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 4f76094ea06d..7caa18d5ffc3 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -841,14 +841,17 @@ static void display_histogram(struct perf_ftrace *ftrace, int buckets[]) bar_len = buckets[0] * bar_total / total; - printf(" %4d - %4d %s | %10d | %.*s%*s |\n", - 0, min_latency ?: 1, use_nsec ? "ns" : "us", - buckets[0], bar_len, bar, bar_total - bar_len, ""); + if (!ftrace->hide_empty || buckets[0]) + printf(" %4d - %4d %s | %10d | %.*s%*s |\n", + 0, min_latency ?: 1, use_nsec ? "ns" : "us", + buckets[0], bar_len, bar, bar_total - bar_len, ""); for (i = 1; i < bucket_num - 1; i++) { unsigned int start, stop; const char *unit = use_nsec ? "ns" : "us"; + if (ftrace->hide_empty && !buckets[i]) + continue; if (!ftrace->bucket_range) { start = (1 << (i - 1)); stop = 1 << i; @@ -884,6 +887,8 @@ print_bucket_info: } bar_len = buckets[bucket_num - 1] * bar_total / total; + if (ftrace->hide_empty && !buckets[bucket_num - 1]) + goto print_stats; if (!ftrace->bucket_range) { printf(" %4d - %-4s %s", 1, "...", use_nsec ? "ms" : "s "); } else { @@ -902,6 +907,7 @@ print_bucket_info: printf(" | %10d | %.*s%*s |\n", buckets[bucket_num - 1], bar_len, bar, bar_total - bar_len, ""); +print_stats: printf("\n# statistics (in %s)\n", ftrace->use_nsec ? "nsec" : "usec"); printf(" total time: %20.0f\n", latency_stats.mean * latency_stats.n); printf(" avg time: %20.0f\n", latency_stats.mean); @@ -1645,6 +1651,8 @@ int cmd_ftrace(int argc, const char **argv) "Minimum latency (1st bucket). Works only with --bucket-range."), OPT_UINTEGER(0, "max-latency", &ftrace.max_latency, "Maximum latency (last bucket). Works only with --bucket-range."), + OPT_BOOLEAN(0, "hide-empty", &ftrace.hide_empty, + "Hide empty buckets in the histogram"), OPT_PARENT(common_options), }; const struct option profile_options[] = { diff --git a/tools/perf/util/ftrace.h b/tools/perf/util/ftrace.h index 395f97b203ea..a9bc47da83a5 100644 --- a/tools/perf/util/ftrace.h +++ b/tools/perf/util/ftrace.h @@ -25,6 +25,7 @@ struct perf_ftrace { unsigned int min_latency; unsigned int max_latency; unsigned int bucket_num; + bool hide_empty; int graph_depth; int func_stack_trace; int func_irq_info;