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Message-ID: <20250825211204.2784695-4-irogers@google.com>
Date: Mon, 25 Aug 2025 14:12:04 -0700
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>,
Kan Liang <kan.liang@...ux.intel.com>, James Clark <james.clark@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Yoshihiro Furudera <fj5100bi@...itsu.com>,
Dapeng Mi <dapeng1.mi@...ux.intel.com>, Howard Chu <howardchu95@...il.com>,
Thomas Falcon <thomas.falcon@...el.com>, Andi Kleen <ak@...ux.intel.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Xudong Hao <xudong.hao@...el.com>
Subject: [PATCH v1 3/3] perf parse-events: Add 'X' modifier to exclude an
event from being regrouped
The function parse_events__sort_events_and_fix_groups is needed to fix
uncore events like:
```
$ perf stat -e '{data_read,data_write}' ...
```
so that the multiple uncore PMUs have a group each of data_read and
data_write events.
The same function will perform architecture sorting and group fixing,
in particular for Intel topdown/perf-metric events. Grouping multiple
perf metric events together causes perf_event_open to fail as the
group can only support one. This means command lines like:
```
$ perf stat -e 'slots,slots' ...
```
fail as the slots events are forced into a group together to try to
satisfy the perf-metric event constraints.
As the user may know better than
parse_events__sort_events_and_fix_groups add a 'X' modifier to skip
its regrouping behavior. This allows the following to succeed rather
than fail on the second slots event being opened:
```
$ perf stat -e 'slots,slots:X' -a sleep 1
Performance counter stats for 'system wide':
6,834,154,071 cpu_core/slots/ (50.13%)
5,548,629,453 cpu_core/slots/X (49.87%)
1.002634606 seconds time elapsed
```
Reported-by: Xudong Hao <xudong.hao@...el.com>
Reported-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
Closes: https://lore.kernel.org/lkml/20250822082233.1850417-1-dapeng1.mi@linux.intel.com/
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
tools/perf/Documentation/perf-list.txt | 1 +
tools/perf/util/evsel.h | 1 +
tools/perf/util/parse-events.c | 5 +++--
tools/perf/util/parse-events.h | 1 +
tools/perf/util/parse-events.l | 5 +++--
5 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt
index 28215306a78a..a5039d1614f9 100644
--- a/tools/perf/Documentation/perf-list.txt
+++ b/tools/perf/Documentation/perf-list.txt
@@ -73,6 +73,7 @@ counted. The following modifiers exist:
e - group or event are exclusive and do not share the PMU
b - use BPF aggregration (see perf stat --bpf-counters)
R - retire latency value of the event
+ X - don't regroup the event to match PMUs
The 'p' modifier can be used for specifying how precise the instruction
address should be. The 'p' modifier can be specified multiple times:
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index e927a3a4fe0e..03f9f22e3a0c 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -89,6 +89,7 @@ struct evsel {
bool use_config_name;
bool skippable;
bool retire_lat;
+ bool dont_regroup;
int bpf_fd;
struct bpf_object *bpf_obj;
struct list_head config_terms;
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 8282ddf68b98..43de19551c81 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1892,6 +1892,8 @@ static int parse_events__modifier_list(struct parse_events_state *parse_state,
evsel->bpf_counter = true;
if (mod.retire_lat)
evsel->retire_lat = true;
+ if (mod.dont_regroup)
+ evsel->dont_regroup = true;
}
return 0;
}
@@ -2188,13 +2190,12 @@ static int parse_events__sort_events_and_fix_groups(struct list_head *list)
* Set the group leader respecting the given groupings and that
* groups can't span PMUs.
*/
- if (!cur_leader) {
+ if (!cur_leader || pos->dont_regroup) {
cur_leader = pos;
cur_leaders_grp = &pos->core;
if (pos_force_grouped)
force_grouped_leader = pos;
}
-
cur_leader_pmu_name = cur_leader->group_pmu_name;
if (strcmp(cur_leader_pmu_name, pos_pmu_name)) {
/* PMU changed so the group/leader must change. */
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 62dc7202e3ba..a5c5fc39fd6f 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -216,6 +216,7 @@ struct parse_events_modifier {
bool guest : 1; /* 'G' */
bool host : 1; /* 'H' */
bool retire_lat : 1; /* 'R' */
+ bool dont_regroup : 1; /* 'X' */
};
int parse_events__modifier_event(struct parse_events_state *parse_state, void *loc,
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 2034590eb789..294e943bcdb4 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -206,6 +206,7 @@ static int modifiers(struct parse_events_state *parse_state, yyscan_t scanner)
CASE('e', exclusive);
CASE('b', bpf);
CASE('R', retire_lat);
+ CASE('X', dont_regroup);
default:
return PE_ERROR;
}
@@ -251,10 +252,10 @@ term_name {name_start}[a-zA-Z0-9_*?.\[\]!\-:]*
quoted_name [\']{name_start}[a-zA-Z0-9_*?.\[\]!\-:,\.=]*[\']
drv_cfg_term [a-zA-Z0-9_\.]+(=[a-zA-Z0-9_*?\.:]+)?
/*
- * If you add a modifier you need to update check_modifier().
+ * If you add a modifier you need to update modifiers().
* Also, the letters in modifier_event must not be in modifier_bp.
*/
-modifier_event [ukhpPGHSDIWebR]{1,16}
+modifier_event [ukhpPGHSDIWebRX]{1,17}
modifier_bp [rwx]{1,3}
lc_type (L1-dcache|l1-d|l1d|L1-data|L1-icache|l1-i|l1i|L1-instruction|LLC|L2|dTLB|d-tlb|Data-TLB|iTLB|i-tlb|Instruction-TLB|branch|branches|bpu|btb|bpc|node)
lc_op_result (load|loads|read|store|stores|write|prefetch|prefetches|speculative-read|speculative-load|refs|Reference|ops|access|misses|miss)
--
2.51.0.261.g7ce5a0a67e-goog
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