Re: [PATCH v7] perf stat: Fix wrong skipping for per-die aggregation

From: Jiri Olsa
Date: Sat Jan 23 2021 - 17:59:16 EST


On Thu, Jan 21, 2021 at 12:21:36PM +0800, Jin, Yao wrote:

sNIP

> mask = hashmap__new(pkg_id_hash, pkg_id_equal, NULL);
> d = cpu_map__get_die(cpus, cpu, NULL).die;
> key = (size_t)d << KEY_SHIFT | s; /* s is socket id */
> if (hashmap__find(mask, (void *)key, NULL))
> *skip = true;
> else
> ret = hashmap__add(mask, (void *)key, (void *)1);
>
> If we use 'unsigned long' to replace 'size_t', it reports the build error for 32 bits:
>
> stat.c:320:23: warning: passing argument 1 of ‘hashmap__new’ from
> incompatible pointer type [-Wincompatible-pointer-types]
> mask = hashmap__new(pkg_id_hash, pkg_id_equal, NULL);
> ^~~~~~~~~~~
> In file included from stat.c:16:
> hashmap.h:75:17: note: expected ‘hashmap_hash_fn’ {aka ‘unsigned int
> (*)(const void *, void *)’} but argument is of type ‘long unsigned int
> (*)(const void *, void *)’
>
> If we use "unsigned int", it's not good for 64 bits. So I still use 'size_t' in this patch.
>
> Any comments for this idea (using conditional compilation)?

isn't it simpler to allocate the key then? like below
(just compile tested)

jirka


---
diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index 5aba8fa92386..195fda142c98 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c
@@ -276,19 +276,31 @@ void evlist__save_aggr_prev_raw_counts(struct evlist *evlist)

static void zero_per_pkg(struct evsel *counter)
{
- if (counter->per_pkg_mask)
+ struct hashmap_entry *cur;
+ size_t bkt;
+
+ if (counter->per_pkg_mask) {
+ hashmap__for_each_entry(counter->per_pkg_mask, cur, bkt)
+ free((char *)cur->key);
+
hashmap__clear(counter->per_pkg_mask);
+ }
}

-static size_t pkg_id_hash(const void *key, void *ctx __maybe_unused)
+static size_t pkg_id_hash(const void *__key, void *ctx __maybe_unused)
{
- return (size_t)key & 0xffff;
+ uint64_t *key = (uint64_t*) __key;
+
+ return *key & 0xffffffff;
}

-static bool pkg_id_equal(const void *key1, const void *key2,
+static bool pkg_id_equal(const void *__key1, const void *__key2,
void *ctx __maybe_unused)
{
- return (size_t)key1 == (size_t)key2;
+ uint64_t *key1 = (uint64_t*) __key1;
+ uint64_t *key2 = (uint64_t*) __key2;
+
+ return *key1 == *key2;
}

static int check_per_pkg(struct evsel *counter,
@@ -297,7 +309,7 @@ static int check_per_pkg(struct evsel *counter,
struct hashmap *mask = counter->per_pkg_mask;
struct perf_cpu_map *cpus = evsel__cpus(counter);
int s, d, ret = 0;
- size_t key;
+ uint64_t *key;

*skip = false;

@@ -338,7 +350,11 @@ static int check_per_pkg(struct evsel *counter,
if (d < 0)
return -1;

- key = (size_t)d << 16 | s;
+ key = malloc(sizeof(*key));
+ if (!key)
+ return -ENOMEM;
+
+ *key = (size_t)d << 32 | s;
if (hashmap__find(mask, (void *)key, NULL))
*skip = true;
else