From dd01b985c52a964ed5b193972e475481fefa0f45 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Wed, 8 Jan 2025 13:00:14 -0800 Subject: [PATCH] perf ftrace: Check min/max latency only with bucket range It's an optional feature and remains 0 when bucket range is not given. And it makes the histogram goes to the last entry always because any latency (num) is greater than or equal to 0. Before: $ sudo ./perf ftrace latency -a -T do_futex sleep 1 # DURATION | COUNT | GRAPH | 0 - 0 us | 0 | | 1 - 2 us | 0 | | 2 - 4 us | 0 | | 4 - 8 us | 0 | | 8 - 16 us | 0 | | 16 - 32 us | 0 | | 32 - 64 us | 0 | | 64 - 128 us | 0 | | 128 - 256 us | 0 | | 256 - 512 us | 0 | | 512 - 1024 us | 0 | | 1 - 2 ms | 0 | | 2 - 4 ms | 0 | | 4 - 8 ms | 0 | | 8 - 16 ms | 0 | | 16 - 32 ms | 0 | | 32 - 64 ms | 0 | | 64 - 128 ms | 0 | | 128 - 256 ms | 0 | | 256 - 512 ms | 0 | | 512 - 1024 ms | 0 | | 1 - ... s | 1353 | ############################################## | After: $ sudo ./perf ftrace latency -a -T do_futex sleep 1 # DURATION | COUNT | GRAPH | 0 - 0 us | 321 | ########### | 1 - 2 us | 132 | #### | 2 - 4 us | 202 | ####### | 4 - 8 us | 188 | ###### | 8 - 16 us | 16 | | 16 - 32 us | 12 | | 32 - 64 us | 30 | # | 64 - 128 us | 98 | ### | 128 - 256 us | 53 | # | 256 - 512 us | 57 | ## | 512 - 1024 us | 9 | | 1 - 2 ms | 9 | | 2 - 4 ms | 1 | | 4 - 8 ms | 98 | ### | 8 - 16 ms | 5 | | 16 - 32 ms | 7 | | 32 - 64 ms | 32 | # | 64 - 128 ms | 10 | | 128 - 256 ms | 10 | | 256 - 512 ms | 2 | | 512 - 1024 ms | 0 | | 1 - ... s | 0 | | Fixes: 690a052a6d85c530 ("perf ftrace latency: Add --max-latency option") Reviewed-by: Gabriele Monaco Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Tested-by: Gabriele Monaco Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250108210015.1188531-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-ftrace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 08c1cc429b27..90cf2c9915a7 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -796,8 +796,10 @@ static void make_histogram(struct perf_ftrace *ftrace, int buckets[], // than the min latency desired. if (num > 0) // 1st entry: [ 1 unit .. bucket_range units ] i = num / ftrace->bucket_range + 1; + if (num >= max_latency - min_latency) + i = NUM_BUCKET -1; } - if (i >= NUM_BUCKET || num >= max_latency - min_latency) + if (i >= NUM_BUCKET) i = NUM_BUCKET - 1; num += min_latency; @@ -1738,7 +1740,7 @@ int cmd_ftrace(int argc, const char **argv) ret = -EINVAL; goto out_delete_filters; } - if (!ftrace.min_latency) { + if (ftrace.bucket_range && !ftrace.min_latency) { /* default min latency should be the bucket range */ ftrace.min_latency = ftrace.bucket_range; } @@ -1749,7 +1751,7 @@ int cmd_ftrace(int argc, const char **argv) ret = -EINVAL; goto out_delete_filters; } - if (!ftrace.max_latency) { + if (ftrace.bucket_range && !ftrace.max_latency) { /* default max latency should depend on bucket range and num_buckets */ ftrace.max_latency = (NUM_BUCKET - 2) * ftrace.bucket_range + ftrace.min_latency; -- 2.50.1