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Message-ID: <20250103231630.928815-1-namhyung@kernel.org>
Date: Fri, 3 Jan 2025 15:16:28 -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
Subject: [PATCH 1/3] perf ftrace: Add --stats option to latency subcommand
Sometimes users also want to see average latency as well as histogram.
The --stats option is to display latency statistics at the end.
$ sudo ./perf ftrace latency -ab --stats -T synchronize_rcu -- ...
# DURATION | COUNT | GRAPH |
0 - 1 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 | 1 | ##### |
16 - 32 ms | 7 | ######################################## |
32 - 64 ms | 0 | |
64 - 128 ms | 0 | |
128 - 256 ms | 0 | |
256 - 512 ms | 0 | |
512 - 1024 ms | 0 | |
1 - ... s | 0 | |
# statistics (in usec)
total time: 171832
avg time: 21479
max time: 30906
min time: 15869
count: 8
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/Documentation/perf-ftrace.txt | 4 ++++
tools/perf/builtin-ftrace.c | 24 ++++++++++++++++++++-
tools/perf/util/bpf_ftrace.c | 16 ++++++++++++--
tools/perf/util/bpf_skel/func_latency.bpf.c | 19 ++++++++++++++++
tools/perf/util/ftrace.h | 4 +++-
5 files changed, 63 insertions(+), 4 deletions(-)
diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt
index eccc0483f7faecad..16b067eb5d84746d 100644
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/tools/perf/Documentation/perf-ftrace.txt
@@ -160,6 +160,10 @@ OPTIONS for 'perf ftrace latency'
-n/--use-nsec). The setting is ignored if the value results in more than
22 buckets.
+--stats::
+ Display latency statistics at the end.
+
+
OPTIONS for 'perf ftrace profile'
---------------------------------
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 834074162a63bf2b..0ac2b20b272bd790 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -43,6 +43,8 @@
static volatile sig_atomic_t workload_exec_errno;
static volatile sig_atomic_t done;
+static struct stats latency_stats; /* for tracepoints */
+
static void sig_handler(int sig __maybe_unused)
{
done = true;
@@ -801,6 +803,13 @@ static void make_histogram(struct perf_ftrace *ftrace, int buckets[],
do_inc:
buckets[i]++;
+ if (ftrace->stats) {
+ if (num >= min_latency)
+ num += min_latency;
+
+ update_stats(&latency_stats, num);
+ }
+
next:
/* empty the line buffer for the next output */
linebuf[0] = '\0';
@@ -894,6 +903,14 @@ static void display_histogram(struct perf_ftrace *ftrace, int buckets[])
printf(" | %10d | %.*s%*s |\n", buckets[NUM_BUCKET - 1],
bar_len, bar, bar_total - bar_len, "");
+ if (ftrace->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);
+ printf(" max time: %20"PRIu64"\n", latency_stats.max);
+ printf(" min time: %20"PRIu64"\n", latency_stats.min);
+ printf(" count: %20.0f\n", latency_stats.n);
+ }
}
static int prepare_func_latency(struct perf_ftrace *ftrace)
@@ -932,6 +949,9 @@ static int prepare_func_latency(struct perf_ftrace *ftrace)
if (fd < 0)
pr_err("failed to open trace_pipe\n");
+ if (ftrace->stats)
+ init_stats(&latency_stats);
+
put_tracing_file(trace_file);
return fd;
}
@@ -961,7 +981,7 @@ static int stop_func_latency(struct perf_ftrace *ftrace)
static int read_func_latency(struct perf_ftrace *ftrace, int buckets[])
{
if (ftrace->target.use_bpf)
- return perf_ftrace__latency_read_bpf(ftrace, buckets);
+ return perf_ftrace__latency_read_bpf(ftrace, buckets, &latency_stats);
return 0;
}
@@ -1620,6 +1640,8 @@ 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 and total buckets less than 22."),
+ OPT_BOOLEAN(0, "stats", &ftrace.stats,
+ "Collect function latency stats too"),
OPT_PARENT(common_options),
};
const struct option profile_options[] = {
diff --git a/tools/perf/util/bpf_ftrace.c b/tools/perf/util/bpf_ftrace.c
index bc484e65fb8f69ca..ecd5e16df9730e0d 100644
--- a/tools/perf/util/bpf_ftrace.c
+++ b/tools/perf/util/bpf_ftrace.c
@@ -11,6 +11,7 @@
#include "util/debug.h"
#include "util/evlist.h"
#include "util/bpf_counter.h"
+#include "util/stat.h"
#include "util/bpf_skel/func_latency.skel.h"
@@ -53,6 +54,7 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
}
skel->rodata->use_nsec = ftrace->use_nsec;
+ skel->rodata->stats = ftrace->stats;
set_max_rlimit();
@@ -86,6 +88,9 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace)
}
}
+ if (ftrace->stats)
+ skel->bss->min = INT64_MAX;
+
skel->links.func_begin = bpf_program__attach_kprobe(skel->progs.func_begin,
false, func->name);
if (IS_ERR(skel->links.func_begin)) {
@@ -121,8 +126,8 @@ int perf_ftrace__latency_stop_bpf(struct perf_ftrace *ftrace __maybe_unused)
return 0;
}
-int perf_ftrace__latency_read_bpf(struct perf_ftrace *ftrace __maybe_unused,
- int buckets[])
+int perf_ftrace__latency_read_bpf(struct perf_ftrace *ftrace,
+ int buckets[], struct stats *stats)
{
int i, fd, err;
u32 idx;
@@ -146,6 +151,13 @@ int perf_ftrace__latency_read_bpf(struct perf_ftrace *ftrace __maybe_unused,
buckets[idx] += hist[i];
}
+ if (ftrace->stats && skel->bss->count) {
+ stats->mean = skel->bss->total / skel->bss->count;
+ stats->n = skel->bss->count;
+ stats->max = skel->bss->max;
+ stats->min = skel->bss->min;
+ }
+
free(hist);
return 0;
}
diff --git a/tools/perf/util/bpf_skel/func_latency.bpf.c b/tools/perf/util/bpf_skel/func_latency.bpf.c
index 4df54e1b1411b10a..9b68eea8fd444699 100644
--- a/tools/perf/util/bpf_skel/func_latency.bpf.c
+++ b/tools/perf/util/bpf_skel/func_latency.bpf.c
@@ -38,12 +38,19 @@ struct {
int enabled = 0;
+// stats
+__s64 total;
+__s64 count;
+__s64 max;
+__s64 min;
+
const volatile int has_cpu = 0;
const volatile int has_task = 0;
const volatile int use_nsec = 0;
const volatile unsigned int bucket_range;
const volatile unsigned int min_latency;
const volatile unsigned int max_latency;
+const volatile int stats = 0;
SEC("kprobe/func")
int BPF_PROG(func_begin)
@@ -136,6 +143,18 @@ int BPF_PROG(func_end)
return 0;
*hist += 1;
+
+ if (stats) {
+ delta /= cmp_base;
+
+ __sync_fetch_and_add(&total, delta);
+ __sync_fetch_and_add(&count, 1);
+
+ if (delta > max)
+ max = delta;
+ if (delta < min)
+ min = delta;
+ }
}
return 0;
diff --git a/tools/perf/util/ftrace.h b/tools/perf/util/ftrace.h
index f218703063f74786..76038ed712085fbc 100644
--- a/tools/perf/util/ftrace.h
+++ b/tools/perf/util/ftrace.h
@@ -7,6 +7,7 @@
struct evlist;
struct hashamp;
+struct stats;
struct perf_ftrace {
struct evlist *evlist;
@@ -23,6 +24,7 @@ struct perf_ftrace {
unsigned int bucket_range;
unsigned int min_latency;
unsigned int max_latency;
+ bool stats;
int graph_depth;
int func_stack_trace;
int func_irq_info;
@@ -46,7 +48,7 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace);
int perf_ftrace__latency_start_bpf(struct perf_ftrace *ftrace);
int perf_ftrace__latency_stop_bpf(struct perf_ftrace *ftrace);
int perf_ftrace__latency_read_bpf(struct perf_ftrace *ftrace,
- int buckets[]);
+ int buckets[], struct stats *stats);
int perf_ftrace__latency_cleanup_bpf(struct perf_ftrace *ftrace);
#else /* !HAVE_BPF_SKEL */
--
2.47.1.613.gc27f4b7a9f-goog
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