Re: [PATCH 2/2] perf parse-events: Remove "not supported" hybrid cache events
From: Xing Zhengjun
Date: Thu Sep 22 2022 - 04:04:13 EST
On 9/22/2022 11:16 AM, Ian Rogers wrote:
On Wed, Sep 21, 2022 at 6:47 PM <zhengjun.xing@xxxxxxxxxxxxxxx> wrote:
From: Zhengjun Xing <zhengjun.xing@xxxxxxxxxxxxxxx>
By default, we create two hybrid cache events, one is for cpu_core, and
another is for cpu_atom. But Some hybrid hardware cache events are only
available on one CPU PMU. For example, the 'L1-dcache-load-misses' is only
available on cpu_core, while the 'L1-icache-loads' is only available on
cpu_atom. We need to remove "not supported" hybrid cache events. By
extending is_event_supported() to global API and using it to check if the
hybrid cache events are supported before being created, we can remove the
"not supported" hybrid cache events.
Before:
# ./perf stat -e L1-dcache-load-misses,L1-icache-loads -a sleep 1
Performance counter stats for 'system wide':
52,570 cpu_core/L1-dcache-load-misses/
<not supported> cpu_atom/L1-dcache-load-misses/
<not supported> cpu_core/L1-icache-loads/
1,471,817 cpu_atom/L1-icache-loads/
1.004915229 seconds time elapsed
After:
# ./perf stat -e L1-dcache-load-misses,L1-icache-loads -a sleep 1
Performance counter stats for 'system wide':
54,510 cpu_core/L1-dcache-load-misses/
1,441,286 cpu_atom/L1-icache-loads/
1.005114281 seconds time elapsed
Fixes: 30def61f64ba ("perf parse-events: Create two hybrid cache events")
Signed-off-by: Zhengjun Xing <zhengjun.xing@xxxxxxxxxxxxxxx>
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
tools/perf/util/parse-events-hybrid.c | 8 +++++++-
tools/perf/util/print-events.c | 2 +-
tools/perf/util/print-events.h | 3 ++-
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/parse-events-hybrid.c b/tools/perf/util/parse-events-hybrid.c
index 284f8eabd3b9..cf2e1c2e968f 100644
--- a/tools/perf/util/parse-events-hybrid.c
+++ b/tools/perf/util/parse-events-hybrid.c
@@ -14,6 +14,7 @@
#include "pmu.h"
#include "pmu-hybrid.h"
#include "perf.h"
+#include "print-events.h"
static void config_hybrid_attr(struct perf_event_attr *attr,
int type, int pmu_type)
@@ -48,13 +49,18 @@ static int create_event_hybrid(__u32 config_type, int *idx,
__u64 config = attr->config;
config_hybrid_attr(attr, config_type, pmu->type);
+
+ if (attr->type == PERF_TYPE_HW_CACHE
+ && !is_event_supported(attr->type, attr->config))
+ goto out;
A comment to explain this would be useful.
Thanks, I will add a comment in the next version.
+
evsel = parse_events__add_event_hybrid(list, idx, attr, name, metric_id,
pmu, config_terms);
if (evsel)
evsel->pmu_name = strdup(pmu->name);
else
return -ENOMEM;
For consistency should this use the "goto" pattern now? You can also
handle the ENOMEM case for strdup.
Yes, I will add a strdup check in the next version.
-
+out:
attr->type = type;
attr->config = config;
return 0;
diff --git a/tools/perf/util/print-events.c b/tools/perf/util/print-events.c
index 04050d4f6db8..fa5cc94cfcfe 100644
--- a/tools/perf/util/print-events.c
+++ b/tools/perf/util/print-events.c
@@ -239,7 +239,7 @@ void print_sdt_events(const char *subsys_glob, const char *event_glob,
strlist__delete(sdtlist);
}
-static bool is_event_supported(u8 type, u64 config)
+bool is_event_supported(u8 type, u64 config)
This makes me tempted to say this function should be in parse-events.c.
"is_event_supported" move to parse-events.c should be better, I will do
it in the next version.
Thanks,
Ian
{
bool ret = true;
int open_return;
diff --git a/tools/perf/util/print-events.h b/tools/perf/util/print-events.h
index 1da9910d83a6..ad2902fd0507 100644
--- a/tools/perf/util/print-events.h
+++ b/tools/perf/util/print-events.h
@@ -1,14 +1,15 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __PERF_PRINT_EVENTS_H
#define __PERF_PRINT_EVENTS_H
-
#include <stdbool.h>
+#include <linux/types.h>
struct event_symbol;
void print_events(const char *event_glob, bool name_only, bool quiet_flag,
bool long_desc, bool details_flag, bool deprecated,
const char *pmu_name);
+bool is_event_supported(u8 type, u64 config);
int print_hwcache_events(const char *event_glob, bool name_only);
void print_sdt_events(const char *subsys_glob, const char *event_glob,
bool name_only);
--
2.25.1
--
Zhengjun Xing