[PATCH v1 6/6] perf tools: Add/use PMU reverse lookup from config to name

From: Ian Rogers
Date: Thu Mar 07 2024 - 03:15:52 EST


Add perf_pmu__name_from_config that does a reverse lookup from a
config number to an alias name. The lookup is expensive as the config
is computed for every alias by filling in a perf_event_attr, but this
is only done when verbose output is enabled. The lookup also only
considers config, and not config1, config2 or config3.

An example of the output:
```
$ perf stat -vv -e data_read true
..
perf_event_attr:
type 24 (uncore_imc_free_running_0)
size 136
config 0x20ff (data_read)
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
exclude_guest 1
..
```

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/util/perf_event_attr_fprintf.c | 10 ++++++++--
tools/perf/util/pmu.c | 19 +++++++++++++++++++
tools/perf/util/pmu.h | 1 +
3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/perf_event_attr_fprintf.c b/tools/perf/util/perf_event_attr_fprintf.c
index 29e66835da3a..59fbbba79697 100644
--- a/tools/perf/util/perf_event_attr_fprintf.c
+++ b/tools/perf/util/perf_event_attr_fprintf.c
@@ -222,8 +222,14 @@ static void __p_config_tracepoint_id(char *buf, size_t size, u64 value)
}
#endif

-static void __p_config_id(char *buf, size_t size, u32 type, u64 value)
+static void __p_config_id(struct perf_pmu *pmu, char *buf, size_t size, u32 type, u64 value)
{
+ const char *name = perf_pmu__name_from_config(pmu, value);
+
+ if (name) {
+ print_id_hex(name);
+ return;
+ }
switch (type) {
case PERF_TYPE_HARDWARE:
return __p_config_hw_id(buf, size, value);
@@ -252,7 +258,7 @@ static void __p_config_id(char *buf, size_t size, u32 type, u64 value)
#define p_branch_sample_type(val) __p_branch_sample_type(buf, BUF_SIZE, val)
#define p_read_format(val) __p_read_format(buf, BUF_SIZE, val)
#define p_type_id(val) __p_type_id(pmu, buf, BUF_SIZE, val)
-#define p_config_id(val) __p_config_id(buf, BUF_SIZE, attr->type, val)
+#define p_config_id(val) __p_config_id(pmu, buf, BUF_SIZE, attr->type, val)

#define PRINT_ATTRn(_n, _f, _p, _a) \
do { \
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 904725f03d29..f26b06912a8a 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -2139,3 +2139,22 @@ void perf_pmu__delete(struct perf_pmu *pmu)
zfree(&pmu->id);
free(pmu);
}
+
+const char *perf_pmu__name_from_config(struct perf_pmu *pmu, u64 config)
+{
+ struct perf_pmu_alias *event;
+
+ if (!pmu)
+ return NULL;
+
+ list_for_each_entry(event, &pmu->aliases, list) {
+ struct perf_event_attr attr = {.config = 0,};
+ int ret = perf_pmu__config(pmu, &attr, &event->terms, NULL);
+
+ if (ret)
+ return NULL;
+ if (config == attr.config)
+ return event->name;
+ }
+ return NULL;
+}
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 9f5284b29ecf..152700f78455 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -276,5 +276,6 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
struct perf_pmu *perf_pmu__create_placeholder_core_pmu(struct list_head *core_pmus);
void perf_pmu__delete(struct perf_pmu *pmu);
struct perf_pmu *perf_pmus__find_core_pmu(void);
+const char *perf_pmu__name_from_config(struct perf_pmu *pmu, u64 config);

#endif /* __PMU_H */
--
2.44.0.278.ge034bb2e1d-goog