[PATCH v1 03/25] perf sample: Add evsel to struct perf_sample

Ian Rogers
2026-02-09T17:40:50Z

Add the evsel from evsel__parse_sample into the struct
perf_sample. Sometimes we want to alter the evsel associated with a
sample, such as with off-cpu bpf-output events. In general the evsel
and perf_sample are passed as a pair, but this makes an altered evsel
something of a chore to keep checking for and setting up. Later
patches will remove passing an evsel with the perf_sample and switch
to just using the perf_sample's value.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/builtin-inject.c | 10 ++++++---
tools/perf/builtin-script.c | 4 ++++
tools/perf/tests/hists_cumulate.c | 2 +-
tools/perf/tests/hists_filter.c | 1 +
tools/perf/tests/hists_output.c | 2 +-
tools/perf/util/evsel.c | 1 +
tools/perf/util/sample.h | 3 +++
tools/perf/util/session.c | 35 +++++++++++++++++++------------
8 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 3d2556213599..8ae76bf5253e 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -133,7 +133,7 @@ struct perf_inject {
struct perf_file_section secs[HEADER_FEAT_BITS];
struct guest_session guest_session;
struct strlist *known_build_ids;
- const struct evsel *mmap_evsel;
+ struct evsel *mmap_evsel;
struct ip_callchain *raw_callchain;
};

@@ -519,7 +519,7 @@ static struct dso *findnew_dso(int pid, int tid, const char *filename,
* processing mmap events. If not stashed, search the evlist for the first mmap
* gathering event.
*/
-static const struct evsel *inject__mmap_evsel(struct perf_inject *inject)
+static struct evsel *inject__mmap_evsel(struct perf_inject *inject)
{
struct evsel *pos;

@@ -1007,6 +1007,7 @@ int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *e
.machine = machine,
.mmap_evsel = inject__mmap_evsel(inject),
};
+ struct evsel *saved_evsel = sample->evsel;

addr_location__init(&al);
thread = machine__findnew_thread(machine, sample->pid, sample->tid);
@@ -1021,9 +1022,10 @@ int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *e
/*sample_in_dso=*/true);
}

+ sample->evsel = inject__mmap_evsel(inject);
sample__for_each_callchain_node(thread, evsel, sample, PERF_MAX_STACK_DEPTH,
/*symbols=*/false, mark_dso_hit_callback, &args);
-
+ sample->evsel = saved_evsel;
thread__put(thread);
repipe:
perf_event__repipe(tool, event, sample, machine);
@@ -1100,6 +1102,7 @@ static int perf_inject__sched_stat(const struct perf_tool *tool,
evsel__parse_sample(evsel, event_sw, &sample_sw);

perf_sample__init(&sample_sw, /*all=*/false);
+ sample_sw.evsel = evsel;
sample_sw.period = sample->period;
sample_sw.time = sample->time;
perf_event__synthesize_sample(event_sw, evsel->core.attr.sample_type,
@@ -1433,6 +1436,7 @@ static int synthesize_build_id(struct perf_inject *inject, struct dso *dso, pid_
{
struct machine *machine = perf_session__findnew_machine(inject->session, machine_pid);
struct perf_sample synth_sample = {
+ .evsel = inject__mmap_evsel(inject),
.pid = -1,
.tid = -1,
.time = -1,
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 14c6f6c3c4f2..c28897186341 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -2905,8 +2905,12 @@ static int print_event_with_time(const struct perf_tool *tool,
thread = machine__findnew_thread(machine, pid, tid);

if (evsel) {
+ struct evsel *saved_evsel = sample->evsel;
+
+ sample->evsel = evsel;
perf_sample__fprintf_start(script, sample, thread, evsel,
event->header.type, stdout);
+ sample->evsel = saved_evsel;
}

perf_event__fprintf(event, machine, stdout);
diff --git a/tools/perf/tests/hists_cumulate.c b/tools/perf/tests/hists_cumulate.c
index 3eb9ef8d7ec6..606aa926a8fc 100644
--- a/tools/perf/tests/hists_cumulate.c
+++ b/tools/perf/tests/hists_cumulate.c
@@ -81,7 +81,7 @@ static int add_hist_entries(struct hists *hists, struct machine *machine)
{
struct addr_location al;
struct evsel *evsel = hists_to_evsel(hists);
- struct perf_sample sample = { .period = 1000, };
+ struct perf_sample sample = { .evsel = evsel, .period = 1000, };
size_t i;

addr_location__init(&al);
diff --git a/tools/perf/tests/hists_filter.c b/tools/perf/tests/hists_filter.c
index 1cebd20cc91c..cc6b26e373d1 100644
--- a/tools/perf/tests/hists_filter.c
+++ b/tools/perf/tests/hists_filter.c
@@ -70,6 +70,7 @@ static int add_hist_entries(struct evlist *evlist,
};
struct hists *hists = evsel__hists(evsel);

+ sample.evsel = evsel;
/* make sure it has no filter at first */
hists->thread_filter = NULL;
hists->dso_filter = NULL;
diff --git a/tools/perf/tests/hists_output.c b/tools/perf/tests/hists_output.c
index ee5ec8bda60e..7818950d786e 100644
--- a/tools/perf/tests/hists_output.c
+++ b/tools/perf/tests/hists_output.c
@@ -51,7 +51,7 @@ static int add_hist_entries(struct hists *hists, struct machine *machine)
{
struct addr_location al;
struct evsel *evsel = hists_to_evsel(hists);
- struct perf_sample sample = { .period = 100, };
+ struct perf_sample sample = { .evsel = evsel, .period = 100, };
size_t i;

addr_location__init(&al);
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 34ae388750db..a7da54d365a9 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -3220,6 +3220,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
union u64_swap u;

perf_sample__init(data, /*all=*/true);
+ data->evsel = evsel;
data->cpu = data->pid = data->tid = -1;
data->stream_id = data->id = data->time = -1ULL;
data->period = evsel->core.attr.sample_period;
diff --git a/tools/perf/util/sample.h b/tools/perf/util/sample.h
index 3fd2a5e01308..51ea4af452ea 100644
--- a/tools/perf/util/sample.h
+++ b/tools/perf/util/sample.h
@@ -5,6 +5,7 @@
#include <linux/perf_event.h>
#include <linux/types.h>

+struct evsel;
struct machine;
struct thread;

@@ -102,6 +103,8 @@ struct simd_flags {
* and clean up these values.
*/
struct perf_sample {
+ /** @evsel: Backward reference to the evsel used when constructing the sample. */
+ struct evsel *evsel;
/** @ip: The sample event PERF_SAMPLE_IP value. */
u64 ip;
/** @pid: The sample event PERF_SAMPLE_TID pid value. */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index c48e840da7d4..3794d3a04afb 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1257,8 +1257,9 @@ static int deliver_sample_value(struct evlist *evlist,
bool per_thread)
{
struct perf_sample_id *sid = evlist__id2sid(evlist, v->id);
- struct evsel *evsel;
+ struct evsel *saved_evsel = sample->evsel;
u64 *storage = NULL;
+ int ret;

if (sid) {
storage = perf_sample_id__get_period_storage(sid, sample->tid, per_thread);
@@ -1282,8 +1283,10 @@ static int deliver_sample_value(struct evlist *evlist,
if (!sample->period)
return 0;

- evsel = container_of(sid->evsel, struct evsel, core);
- return tool->sample(tool, event, sample, evsel, machine);
+ sample->evsel = container_of(sid->evsel, struct evsel, core);
+ ret = tool->sample(tool, event, sample, sample->evsel, machine);
+ sample->evsel = saved_evsel;
+ return ret;
}

static int deliver_sample_group(struct evlist *evlist,
@@ -1355,13 +1358,16 @@ static int evlist__deliver_deferred_callchain(struct evlist *evlist,
struct machine *machine)
{
struct deferred_event *de, *tmp;
- struct evsel *evsel;
int ret = 0;

if (!tool->merge_deferred_callchains) {
- evsel = evlist__id2evsel(evlist, sample->id);
- return tool->callchain_deferred(tool, event, sample,
- evsel, machine);
+ struct evsel *saved_evsel = sample->evsel;
+
+ sample->evsel = evlist__id2evsel(evlist, sample->id);
+ ret = tool->callchain_deferred(tool, event, sample,
+ sample->evsel, machine);
+ sample->evsel = saved_evsel;
+ return ret;
}

list_for_each_entry_safe(de, tmp, &evlist->deferred_samples, list) {
@@ -1385,9 +1391,9 @@ static int evlist__deliver_deferred_callchain(struct evlist *evlist,
else
orig_sample.deferred_callchain = false;

- evsel = evlist__id2evsel(evlist, orig_sample.id);
+ orig_sample.evsel = evlist__id2evsel(evlist, orig_sample.id);
ret = evlist__deliver_sample(evlist, tool, de->event,
- &orig_sample, evsel, machine);
+ &orig_sample, orig_sample.evsel, machine);

perf_sample__exit(&orig_sample);
list_del(&de->list);
@@ -1410,7 +1416,6 @@ static int session__flush_deferred_samples(struct perf_session *session,
struct evlist *evlist = session->evlist;
struct machine *machine = &session->machines.host;
struct deferred_event *de, *tmp;
- struct evsel *evsel;
int ret = 0;

list_for_each_entry_safe(de, tmp, &evlist->deferred_samples, list) {
@@ -1424,9 +1429,9 @@ static int session__flush_deferred_samples(struct perf_session *session,
break;
}

- evsel = evlist__id2evsel(evlist, sample.id);
+ sample.evsel = evlist__id2evsel(evlist, sample.id);
ret = evlist__deliver_sample(evlist, tool, de->event,
- &sample, evsel, machine);
+ &sample, sample.evsel, machine);

perf_sample__exit(&sample);
list_del(&de->list);
@@ -1451,8 +1456,12 @@ static int machines__deliver_event(struct machines *machines,

dump_event(evlist, event, file_offset, sample, file_path);

- evsel = evlist__id2evsel(evlist, sample->id);
+ if (!sample->evsel)
+ sample->evsel = evlist__id2evsel(evlist, sample->id);
+ else
+ assert(sample->evsel == evlist__id2evsel(evlist, sample->id));

+ evsel = sample->evsel;
machine = machines__find_for_cpumode(machines, event, sample);

switch (event->header.type) {
--
2.53.0.239.g8d8fc8a987-goog