[PATCH v1] perf inject: Fix leader sampling inserting additional samples
From: Ian Rogers
Date: Mon Jul 29 2024 - 18:06:33 EST
The processing of leader samples would turn an individual sample with
a group of read values into multiple samples. Perf inject would pass
through the additional samples increasing the output data file size:
```
$ perf record -g -e "{instructions,cycles}:S" -o perf.orig.data true
$ perf script -D -i perf.orig.data | sed -e 's/perf.orig.data/perf.data/g' > orig.txt
$ perf inject -i perf.orig.data -o perf.new.data
$ perf script -D -i perf.new.data | sed -e 's/perf.new.data/perf.data/g' > new.txt
$ diff -u orig.txt new.txt
--- orig.txt 2024-07-29 14:29:40.606576769 -0700
+++ new.txt 2024-07-29 14:30:04.142737434 -0700
...
-0xc550@xxxxxxxxx [0x30]: event: 3
+0xc550@xxxxxxxxx [0xd0]: event: 9
+.
+. ... raw event: size 208 bytes
+. 0000: 09 00 00 00 01 00 d0 00 fc 72 01 86 ff ff ff ff .........r......
+. 0010: 74 7d 2c 00 74 7d 2c 00 fb c3 79 f9 ba d5 05 00 t},.t},...y.....
+. 0020: e6 cb 1a 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
+. 0030: 02 00 00 00 00 00 00 00 76 01 00 00 00 00 00 00 ........v.......
+. 0040: e6 cb 1a 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
+. 0050: 62 18 00 00 00 00 00 00 f6 cb 1a 00 00 00 00 00 b...............
+. 0060: 00 00 00 00 00 00 00 00 0c 00 00 00 00 00 00 00 ................
+. 0070: 80 ff ff ff ff ff ff ff fc 72 01 86 ff ff ff ff .........r......
+. 0080: f3 0e 6e 85 ff ff ff ff 0c cb 7f 85 ff ff ff ff ..n.............
+. 0090: bc f2 87 85 ff ff ff ff 44 af 7f 85 ff ff ff ff ........D.......
+. 00a0: bd be 7f 85 ff ff ff ff 26 d0 7f 85 ff ff ff ff ........&.......
+. 00b0: 6d a4 ff 85 ff ff ff ff ea 00 20 86 ff ff ff ff m......... .....
+. 00c0: 00 fe ff ff ff ff ff ff 57 14 4f 43 fc 7e 00 00 ........W.OC.~..
+
+1642373909693435 0xc550 [0xd0]: PERF_RECORD_SAMPLE(IP, 0x1): 2915700/2915700: 0xffffffff860172fc period: 1 addr: 0
+... FP chain: nr:12
+..... 0: ffffffffffffff80
+..... 1: ffffffff860172fc
+..... 2: ffffffff856e0ef3
+..... 3: ffffffff857fcb0c
+..... 4: ffffffff8587f2bc
+..... 5: ffffffff857faf44
+..... 6: ffffffff857fbebd
+..... 7: ffffffff857fd026
+..... 8: ffffffff85ffa46d
+..... 9: ffffffff862000ea
+..... 10: fffffffffffffe00
+..... 11: 00007efc434f1457
+... sample_read:
+.... group nr 2
+..... id 00000000001acbe6, value 0000000000000176, lost 0
+..... id 00000000001acbf6, value 0000000000001862, lost 0
+
+0xc620@xxxxxxxxx [0x30]: event: 3
...
```
This behavior is incorrect as in the case above perf inject should
have done nothing. Fix this behavior by disabling separating samples
for a tool that requests it. Only request this for `perf inject` so as
to not affect other perf tools. With the patch and the test above
there are no differences between the orig.txt and new.txt.
Fixes: e4caec0d1af3 ("perf evsel: Add PERF_SAMPLE_READ sample related processing")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/builtin-inject.c | 1 +
tools/perf/util/session.c | 3 +++
tools/perf/util/tool.h | 1 +
3 files changed, 5 insertions(+)
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index a212678d47be..c80fb0f60e61 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -2204,6 +2204,7 @@ int cmd_inject(int argc, const char **argv)
.finished_init = perf_event__repipe_op2_synth,
.compressed = perf_event__repipe_op4_synth,
.auxtrace = perf_event__repipe_auxtrace,
+ .dont_split_sample_group = true,
},
.input_name = "-",
.samples = LIST_HEAD_INIT(inject.samples),
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 5596bed1b8c8..080242c69196 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1511,6 +1511,9 @@ static int deliver_sample_group(struct evlist *evlist,
int ret = -EINVAL;
struct sample_read_value *v = sample->read.group.values;
+ if (tool->dont_split_sample_group)
+ return deliver_sample_value(evlist, tool, event, sample, v, machine);
+
sample_read_group__for_each(v, sample->read.group.nr, read_format) {
ret = deliver_sample_value(evlist, tool, event, sample, v,
machine);
diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
index c957fb849ac6..62bbc9cec151 100644
--- a/tools/perf/util/tool.h
+++ b/tools/perf/util/tool.h
@@ -85,6 +85,7 @@ struct perf_tool {
bool namespace_events;
bool cgroup_events;
bool no_warn;
+ bool dont_split_sample_group;
enum show_feature_header show_feat_hdr;
};
--
2.46.0.rc1.232.g9752f9e123-goog