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Message-ID: <20250108210015.1188531-1-namhyung@kernel.org>
Date: Wed, 8 Jan 2025 13:00:14 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Kan Liang <kan.liang@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-perf-users@...r.kernel.org,
Gabriele Monaco <gmonaco@...hat.com>
Subject: [PATCH 1/2] 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")
Cc: Gabriele Monaco <gmonaco@...hat.com>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
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 08c1cc429b27e169..90cf2c9915a7e35b 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;
--
2.47.1.613.gc27f4b7a9f-goog
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