summaryrefslogtreecommitdiff
path: root/tools/perf/arch/x86
diff options
context:
space:
mode:
authorDapeng Mi <dapeng1.mi@linux.intel.com>2024-09-13 08:47:08 +0000
committerNamhyung Kim <namhyung@kernel.org>2024-09-30 15:23:44 -0700
commit1e53e9d1787babb1544eaec7c7fdcb78a4a20a13 (patch)
tree73eddd1bf36f961d0877c420416974536599514e /tools/perf/arch/x86
parent39820ced2aa1fb2453294909651dfc7dd6e6e028 (diff)
perf x86/topdown: Correct leader selection with sample_read enabled
Addresses an issue where, in the absence of a topdown metrics event within a sampling group, the slots event was incorrectly bypassed as the sampling leader when sample_read was enabled. perf record -e '{slots,branches}:S' -c 10000 -vv sleep 1 In this case, the slots event should be sampled as leader but the branches event is sampled in fact like the verbose output shows. perf_event_attr: type 4 (cpu) size 168 config 0x400 (slots) sample_type IP|TID|TIME|READ|CPU|IDENTIFIER read_format ID|GROUP|LOST disabled 1 sample_id_all 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 5 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 168 config 0x4 (PERF_COUNT_HW_BRANCH_INSTRUCTIONS) { sample_period, sample_freq } 10000 sample_type IP|TID|TIME|READ|CPU|IDENTIFIER read_format ID|GROUP|LOST sample_id_all 1 exclude_guest 1 The sample period of slots event instead of branches event is reset to 0. This fix ensures the slots event remains the leader under these conditions. Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com> Cc: Yongwei Ma <yongwei.ma@intel.com> Link: https://lore.kernel.org/r/20240913084712.13861-3-dapeng1.mi@linux.intel.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'tools/perf/arch/x86')
-rw-r--r--tools/perf/arch/x86/util/topdown.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
index 49f25d67ed77..cb2c64928bc4 100644
--- a/tools/perf/arch/x86/util/topdown.c
+++ b/tools/perf/arch/x86/util/topdown.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include "api/fs/fs.h"
#include "util/evsel.h"
+#include "util/evlist.h"
#include "util/pmu.h"
#include "util/pmus.h"
#include "util/topdown.h"
@@ -87,11 +88,24 @@ bool arch_is_topdown_metrics(const struct evsel *evsel)
*/
bool arch_topdown_sample_read(struct evsel *leader)
{
+ struct evsel *evsel;
+
if (!evsel__sys_has_perf_metrics(leader))
return false;
- if (arch_is_topdown_slots(leader))
- return true;
+ if (!arch_is_topdown_slots(leader))
+ return false;
+
+ /*
+ * If slots event as leader event but no topdown metric events
+ * in group, slots event should still sample as leader.
+ */
+ evlist__for_each_entry(leader->evlist, evsel) {
+ if (evsel->core.leader != leader->core.leader)
+ return false;
+ if (evsel != leader && arch_is_topdown_metrics(evsel))
+ return true;
+ }
return false;
}