diff mbox series

[1/4] perf annotate: Add a hashmap for symbol histogram

Message ID 20240228005230.287113-2-namhyung@kernel.org
State New
Headers
Series perf annotate: Improve memory usage for symbol histogram |

Commit Message

Namhyung Kim Feb. 28, 2024, 12:52 a.m. UTC 
  Now symbol histogram uses an array to save per-offset sample counts.
But it wastes a lot of memory if the symbol has a few samples only.
Add a hashmap to save values only for actual samples.

For now, it has duplicate histogram (one in the existing array and
another in the new hash map).  Once it can convert to use the hash
in all places, we can get rid of the array later.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/annotate.c | 40 +++++++++++++++++++++++++++++++++++++-
 tools/perf/util/annotate.h |  2 ++
 2 files changed, 41 insertions(+), 1 deletion(-)

Comments

Namhyung Kim Feb. 28, 2024, 5:21 a.m. UTC | #1 
On Tue, Feb 27, 2024 at 5:20 PM Ian Rogers <irogers@google.com> wrote:
>
> On Tue, Feb 27, 2024 at 4:52 PM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > Now symbol histogram uses an array to save per-offset sample counts.
> > But it wastes a lot of memory if the symbol has a few samples only.
> > Add a hashmap to save values only for actual samples.
> >
> > For now, it has duplicate histogram (one in the existing array and
> > another in the new hash map).  Once it can convert to use the hash
> > in all places, we can get rid of the array later.
> >
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
[SNIP]
> > diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> > index 94435607c958..a2b0c8210740 100644
> > --- a/tools/perf/util/annotate.h
> > +++ b/tools/perf/util/annotate.h
> > @@ -12,6 +12,7 @@
> >  #include "symbol_conf.h"
> >  #include "mutex.h"
> >  #include "spark.h"
> > +#include "hashmap.h"
>
> nit: This could just be a forward reference to keep the number of
> header files down.

Sounds good.  Will fix in v2.

Thanks for your review!
Namhyung
diff mbox series

Patch

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 107b264fa41e..7a70e4d35c9b 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -38,6 +38,7 @@ 
 #include "arch/common.h"
 #include "namespaces.h"
 #include "thread.h"
+#include "hashmap.h"
 #include <regex.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
@@ -863,6 +864,17 @@  bool arch__is(struct arch *arch, const char *name)
 	return !strcmp(arch->name, name);
 }
 
+/* symbol histogram: key = offset << 16 | evsel->core.idx */
+static size_t sym_hist_hash(long key, void *ctx __maybe_unused)
+{
+	return (key >> 16) + (key & 0xffff);
+}
+
+static bool sym_hist_equal(long key1, long key2, void *ctx __maybe_unused)
+{
+	return key1 == key2;
+}
+
 static struct annotated_source *annotated_source__new(void)
 {
 	struct annotated_source *src = zalloc(sizeof(*src));
@@ -877,6 +889,8 @@  static __maybe_unused void annotated_source__delete(struct annotated_source *src
 {
 	if (src == NULL)
 		return;
+
+	hashmap__free(src->samples);
 	zfree(&src->histograms);
 	free(src);
 }
@@ -909,6 +923,14 @@  static int annotated_source__alloc_histograms(struct annotated_source *src,
 	src->sizeof_sym_hist = sizeof_sym_hist;
 	src->nr_histograms   = nr_hists;
 	src->histograms	     = calloc(nr_hists, sizeof_sym_hist) ;
+
+	if (src->histograms == NULL)
+		return -1;
+
+	src->samples = hashmap__new(sym_hist_hash, sym_hist_equal, NULL);
+	if (src->samples == NULL)
+		zfree(&src->histograms);
+
 	return src->histograms ? 0 : -1;
 }
 
@@ -920,6 +942,7 @@  void symbol__annotate_zero_histograms(struct symbol *sym)
 	if (notes->src != NULL) {
 		memset(notes->src->histograms, 0,
 		       notes->src->nr_histograms * notes->src->sizeof_sym_hist);
+		hashmap__clear(notes->src->samples);
 	}
 	if (notes->branch && notes->branch->cycles_hist) {
 		memset(notes->branch->cycles_hist, 0,
@@ -983,8 +1006,10 @@  static int __symbol__inc_addr_samples(struct map_symbol *ms,
 				      struct perf_sample *sample)
 {
 	struct symbol *sym = ms->sym;
+	long hash_key;
 	unsigned offset;
 	struct sym_hist *h;
+	struct sym_hist_entry *entry;
 
 	pr_debug3("%s: addr=%#" PRIx64 "\n", __func__, map__unmap_ip(ms->map, addr));
 
@@ -1002,15 +1027,28 @@  static int __symbol__inc_addr_samples(struct map_symbol *ms,
 			 __func__, __LINE__, sym->name, sym->start, addr, sym->end, sym->type == STT_FUNC);
 		return -ENOMEM;
 	}
+
+	hash_key = offset << 16 | evidx;
+	if (!hashmap__find(src->samples, hash_key, &entry)) {
+		entry = zalloc(sizeof(*entry));
+		if (entry == NULL)
+			return -ENOMEM;
+
+		if (hashmap__add(src->samples, hash_key, entry) < 0)
+			return -ENOMEM;
+	}
+
 	h->nr_samples++;
 	h->addr[offset].nr_samples++;
 	h->period += sample->period;
 	h->addr[offset].period += sample->period;
+	entry->nr_samples++;
+	entry->period += sample->period;
 
 	pr_debug3("%#" PRIx64 " %s: period++ [addr: %#" PRIx64 ", %#" PRIx64
 		  ", evidx=%d] => nr_samples: %" PRIu64 ", period: %" PRIu64 "\n",
 		  sym->start, sym->name, addr, addr - sym->start, evidx,
-		  h->addr[offset].nr_samples, h->addr[offset].period);
+		  entry->nr_samples, entry->period);
 	return 0;
 }
 
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 94435607c958..a2b0c8210740 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -12,6 +12,7 @@ 
 #include "symbol_conf.h"
 #include "mutex.h"
 #include "spark.h"
+#include "hashmap.h"
 
 struct hist_browser_timer;
 struct hist_entry;
@@ -280,6 +281,7 @@  struct annotated_source {
 	size_t			sizeof_sym_hist;
 	struct sym_hist		*histograms;
 	struct annotation_line	**offsets;
+	struct hashmap	   	*samples;
 	int    			nr_histograms;
 	int			nr_entries;
 	int			nr_asm_entries;