* [PATCH 0/2] perf stat: Fix uncore metric scaling across aggregation modes
@ 2026-05-20 17:47 Chun-Tse Shao
2026-05-20 17:47 ` [PATCH 1/2] perf stat: Add aggr_nr metric parser support Chun-Tse Shao
0 siblings, 1 reply; 3+ messages in thread
From: Chun-Tse Shao @ 2026-05-20 17:47 UTC (permalink / raw)
To: linux-kernel
Cc: Chun-Tse Shao, peterz, mingo, acme, namhyung, mark.rutland,
alexander.shishkin, jolsa, irogers, adrian.hunter, james.clark,
sandipan.das, leo.yan, thomas.falcon, yang.lee, linux-perf-users
This series fixes a scaling issue for metrics (like lpm_miss_lat) across
different runtime aggregation modes.
Uncore metrics currently use `source_count` to scale events. However,
`source_count` returns the total uncore unit count regardless of the
selected aggregation mode. When evaluating metrics in different
aggregation mode other than `--per-socket`, this incorrectly divides
aggregated uncore events against the total uncore count rather than the
uncores belonging to the aggregation, leading to wrong metric results.
To fix this, we:
1. Introduce the aggr_nr() keyword to the metric parser, which
dynamically resolves to the active units in the current aggregation
group (`aggr->nr`).
2. Update the python metrics to use `aggr_nr` instead of `source_count`,
ensuring correct scaling across all runtime aggregation boundaries.
Before the fix (incorrect low latency in global mode):
$ perf stat -M lpm_miss_lat --metric-only -a -j -- sleep 1
{"ns lpm_miss_lat_rem" : "122.8", "ns lpm_miss_lat_loc" : "114.5"}
$ perf stat -M lpm_miss_lat --per-socket --metric-only -a -j -- sleep 1
{"socket" : "S0", "ns lpm_miss_lat_rem" : "232.1", "ns lpm_miss_lat_loc" : "278.2"}
{"socket" : "S1", "ns lpm_miss_lat_rem" : "233.9", "ns lpm_miss_lat_loc" : "257.5"}
After the fix (correct scaled latency in all aggregation modes):
$ perf stat -M lpm_miss_lat --metric-only -a -j -- sleep 1
{"ns lpm_miss_lat_rem" : "230.0", "ns lpm_miss_lat_loc" : "220.8"}
$ perf stat -M lpm_miss_lat --per-socket --metric-only -a -j -- sleep 1
{"socket" : "S0", "ns lpm_miss_lat_rem" : "232.5", "ns lpm_miss_lat_loc" : "269.9"}
{"socket" : "S1", "ns lpm_miss_lat_rem" : "225.7", "ns lpm_miss_lat_loc" : "262.3"}
Chun-Tse Shao (2):
perf stat: Add aggr_nr metric parser support
perf stat: Use aggr_nr scaling for Intel uncore miss latency metrics
tools/perf/pmu-events/intel_metrics.py | 8 ++++----
tools/perf/pmu-events/metric.py | 11 +++++++++--
tools/perf/util/expr.c | 27 ++++++++++++++++++++++----
tools/perf/util/expr.h | 4 ++++
tools/perf/util/expr.l | 1 +
tools/perf/util/expr.y | 24 ++++++++++++++++-------
tools/perf/util/stat-shadow.c | 4 +++-
7 files changed, 61 insertions(+), 18 deletions(-)
--
2.54.0.669.g59709faab0-goog
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/2] perf stat: Add aggr_nr metric parser support
2026-05-20 17:47 [PATCH 0/2] perf stat: Fix uncore metric scaling across aggregation modes Chun-Tse Shao
@ 2026-05-20 17:47 ` Chun-Tse Shao
0 siblings, 0 replies; 3+ messages in thread
From: Chun-Tse Shao @ 2026-05-20 17:47 UTC (permalink / raw)
To: linux-kernel
Cc: Chun-Tse Shao, peterz, mingo, acme, namhyung, mark.rutland,
alexander.shishkin, jolsa, irogers, adrian.hunter, james.clark,
sandipan.das, leo.yan, thomas.falcon, yang.lee, linux-perf-users
Introduce the `aggr_nr` function to the metric expression parser.
`aggr_nr` allows metric formulas to dynamically utilize the number of
aggregated targets (`aggr->nr`) instead of relying on the static
`source_count` (which represents the static socket or node count).
This adds the `AGGR_NR` token to the lexer and parser, updates the
expression parsing context helpers to store `aggr_nr`, and feeds
`aggr->nr` from the aggregation structure in `prepare_metric`.
---
tools/perf/util/expr.c | 27 +++++++++++++++++++++++----
tools/perf/util/expr.h | 4 ++++
tools/perf/util/expr.l | 1 +
tools/perf/util/expr.y | 24 +++++++++++++++++-------
tools/perf/util/stat-shadow.c | 4 +++-
5 files changed, 48 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
index 644769e92708..8d00805f93c4 100644
--- a/tools/perf/util/expr.c
+++ b/tools/perf/util/expr.c
@@ -27,6 +27,7 @@ struct expr_id_data {
struct {
double val;
int source_count;
+ int aggr_nr;
} val;
struct {
double val;
@@ -151,8 +152,8 @@ int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val)
}
/* Caller must make sure id is allocated */
-int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
- double val, int source_count)
+int expr__add_id_val_source_count_aggr_nr(struct expr_parse_ctx *ctx, const char *id,
+ double val, int source_count, int aggr_nr)
{
struct expr_id_data *data_ptr = NULL, *old_data = NULL;
char *old_key = NULL;
@@ -163,6 +164,7 @@ int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
return -ENOMEM;
data_ptr->val.val = val;
data_ptr->val.source_count = source_count;
+ data_ptr->val.aggr_nr = aggr_nr;
data_ptr->kind = EXPR_ID_DATA__VALUE;
ret = hashmap__set(ctx->ids, id, data_ptr, &old_key, &old_data);
@@ -177,6 +179,14 @@ int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
return ret;
}
+/* Caller must make sure id is allocated */
+int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
+ double val, int source_count)
+{
+ return expr__add_id_val_source_count_aggr_nr(ctx, id, val, source_count, 1);
+}
+
+
int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
{
struct expr_id_data *data_ptr = NULL, *old_data = NULL;
@@ -390,10 +400,19 @@ double expr_id_data__value(const struct expr_id_data *data)
double expr_id_data__source_count(const struct expr_id_data *data)
{
- assert(data->kind == EXPR_ID_DATA__VALUE);
- return data->val.source_count;
+ if (data->kind == EXPR_ID_DATA__VALUE)
+ return data->val.source_count;
+ return 1.0;
}
+double expr_id_data__aggr_nr(const struct expr_id_data *data)
+{
+ if (data->kind == EXPR_ID_DATA__VALUE)
+ return data->val.aggr_nr;
+ return 1.0;
+}
+
+
double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx)
{
double result = NAN;
diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
index c0cec29ddc29..865bb63cdb03 100644
--- a/tools/perf/util/expr.h
+++ b/tools/perf/util/expr.h
@@ -37,6 +37,8 @@ int expr__add_id(struct expr_parse_ctx *ctx, const char *id);
int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val);
int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
double val, int source_count);
+int expr__add_id_val_source_count_aggr_nr(struct expr_parse_ctx *ctx, const char *id,
+ double val, int source_count, int aggr_nr);
int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref);
int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
struct expr_id_data **data);
@@ -53,6 +55,8 @@ int expr__find_ids(const char *expr, const char *one,
double expr_id_data__value(const struct expr_id_data *data);
double expr_id_data__source_count(const struct expr_id_data *data);
+double expr_id_data__aggr_nr(const struct expr_id_data *data);
+
double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx);
double expr__has_event(const struct expr_parse_ctx *ctx, bool compute_ids, const char *id);
double expr__strcmp_cpuid_str(const struct expr_parse_ctx *ctx, bool compute_ids, const char *id);
diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l
index a2fc43159ee9..f16ccff278d0 100644
--- a/tools/perf/util/expr.l
+++ b/tools/perf/util/expr.l
@@ -121,6 +121,7 @@ min { return MIN; }
if { return IF; }
else { return ELSE; }
source_count { return SOURCE_COUNT; }
+aggr_nr { return AGGR_NR; }
has_event { return HAS_EVENT; }
strcmp_cpuid_str { return STRCMP_CPUID_STR; }
NaN { return nan_value(yyscanner); }
diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
index e364790babb5..e20f649354cf 100644
--- a/tools/perf/util/expr.y
+++ b/tools/perf/util/expr.y
@@ -41,7 +41,7 @@ int expr_lex(YYSTYPE * yylval_param , void *yyscanner);
} ids;
}
-%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT HAS_EVENT STRCMP_CPUID_STR EXPR_ERROR
+%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT AGGR_NR HAS_EVENT STRCMP_CPUID_STR EXPR_ERROR
%left MIN MAX IF
%left '|'
%left '^'
@@ -87,8 +87,14 @@ static struct ids union_expr(struct ids ids1, struct ids ids2)
return result;
}
+enum expr_id_kind {
+ EXPR_ID_KIND__VALUE,
+ EXPR_ID_KIND__SOURCE_COUNT,
+ EXPR_ID_KIND__AGGR_NR,
+};
+
static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
- bool compute_ids, bool source_count)
+ bool compute_ids, enum expr_id_kind kind)
{
struct ids result;
@@ -101,9 +107,12 @@ static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
result.val = NAN;
if (expr__resolve_id(ctx, id, &data) == 0) {
- result.val = source_count
- ? expr_id_data__source_count(data)
- : expr_id_data__value(data);
+ if (kind == EXPR_ID_KIND__SOURCE_COUNT)
+ result.val = expr_id_data__source_count(data);
+ else if (kind == EXPR_ID_KIND__AGGR_NR)
+ result.val = expr_id_data__aggr_nr(data);
+ else
+ result.val = expr_id_data__value(data);
}
result.ids = NULL;
free(id);
@@ -201,8 +210,9 @@ expr: NUMBER
$$.val = $1;
$$.ids = NULL;
}
-| ID { $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
-| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
+| ID { $$ = handle_id(ctx, $1, compute_ids, EXPR_ID_KIND__VALUE); }
+| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, EXPR_ID_KIND__SOURCE_COUNT); }
+| AGGR_NR '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, EXPR_ID_KIND__AGGR_NR); }
| HAS_EVENT '(' ID ')'
{
$$.val = expr__has_event(ctx, compute_ids, $3);
diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index bc2d44df7baf..e375f6f942be 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -53,6 +53,7 @@ static int prepare_metric(struct perf_stat_config *config,
for (i = 0; metric_events[i]; i++) {
int source_count = 0, tool_aggr_idx;
+ int aggr_nr = 1;
bool is_tool_time =
tool_pmu__is_time_event(config, metric_events[i], &tool_aggr_idx);
struct perf_stat_evsel *ps = metric_events[i]->stats;
@@ -104,13 +105,14 @@ static int prepare_metric(struct perf_stat_config *config,
}
if (!source_count)
source_count = evsel__source_count(metric_events[i]);
+ aggr_nr = aggr->nr ?: 1;
}
}
n = strdup(evsel__metric_id(metric_events[i]));
if (!n)
return -ENOMEM;
- expr__add_id_val_source_count(pctx, n, val, source_count);
+ expr__add_id_val_source_count_aggr_nr(pctx, n, val, source_count, aggr_nr);
}
for (int j = 0; metric_refs && metric_refs[j].metric_name; j++) {
--
2.54.0.669.g59709faab0-goog
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/2] perf stat: Add aggr_nr metric parser support
2026-05-20 17:58 [PATCH 0/2] perf stat: Fix uncore metric scaling across aggregation modes Chun-Tse Shao
@ 2026-05-20 17:58 ` Chun-Tse Shao
0 siblings, 0 replies; 3+ messages in thread
From: Chun-Tse Shao @ 2026-05-20 17:58 UTC (permalink / raw)
To: linux-kernel
Cc: Chun-Tse Shao, peterz, mingo, acme, namhyung, mark.rutland,
alexander.shishkin, jolsa, irogers, adrian.hunter, james.clark,
leo.yan, thomas.falcon, yang.lee, linux-perf-users
Introduce the `aggr_nr` function to the metric expression parser.
`aggr_nr` allows metric formulas to dynamically utilize the number of
aggregated targets (`aggr->nr`) instead of relying on the static
`source_count` (which represents the static socket or node count).
This adds the `AGGR_NR` token to the lexer and parser, updates the
expression parsing context helpers to store `aggr_nr`, and feeds
`aggr->nr` from the aggregation structure in `prepare_metric`.
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
---
tools/perf/util/expr.c | 27 +++++++++++++++++++++++----
tools/perf/util/expr.h | 4 ++++
tools/perf/util/expr.l | 1 +
tools/perf/util/expr.y | 24 +++++++++++++++++-------
tools/perf/util/stat-shadow.c | 4 +++-
5 files changed, 48 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
index 644769e92708..8d00805f93c4 100644
--- a/tools/perf/util/expr.c
+++ b/tools/perf/util/expr.c
@@ -27,6 +27,7 @@ struct expr_id_data {
struct {
double val;
int source_count;
+ int aggr_nr;
} val;
struct {
double val;
@@ -151,8 +152,8 @@ int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val)
}
/* Caller must make sure id is allocated */
-int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
- double val, int source_count)
+int expr__add_id_val_source_count_aggr_nr(struct expr_parse_ctx *ctx, const char *id,
+ double val, int source_count, int aggr_nr)
{
struct expr_id_data *data_ptr = NULL, *old_data = NULL;
char *old_key = NULL;
@@ -163,6 +164,7 @@ int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
return -ENOMEM;
data_ptr->val.val = val;
data_ptr->val.source_count = source_count;
+ data_ptr->val.aggr_nr = aggr_nr;
data_ptr->kind = EXPR_ID_DATA__VALUE;
ret = hashmap__set(ctx->ids, id, data_ptr, &old_key, &old_data);
@@ -177,6 +179,14 @@ int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
return ret;
}
+/* Caller must make sure id is allocated */
+int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
+ double val, int source_count)
+{
+ return expr__add_id_val_source_count_aggr_nr(ctx, id, val, source_count, 1);
+}
+
+
int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
{
struct expr_id_data *data_ptr = NULL, *old_data = NULL;
@@ -390,10 +400,19 @@ double expr_id_data__value(const struct expr_id_data *data)
double expr_id_data__source_count(const struct expr_id_data *data)
{
- assert(data->kind == EXPR_ID_DATA__VALUE);
- return data->val.source_count;
+ if (data->kind == EXPR_ID_DATA__VALUE)
+ return data->val.source_count;
+ return 1.0;
}
+double expr_id_data__aggr_nr(const struct expr_id_data *data)
+{
+ if (data->kind == EXPR_ID_DATA__VALUE)
+ return data->val.aggr_nr;
+ return 1.0;
+}
+
+
double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx)
{
double result = NAN;
diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
index c0cec29ddc29..865bb63cdb03 100644
--- a/tools/perf/util/expr.h
+++ b/tools/perf/util/expr.h
@@ -37,6 +37,8 @@ int expr__add_id(struct expr_parse_ctx *ctx, const char *id);
int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val);
int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
double val, int source_count);
+int expr__add_id_val_source_count_aggr_nr(struct expr_parse_ctx *ctx, const char *id,
+ double val, int source_count, int aggr_nr);
int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref);
int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
struct expr_id_data **data);
@@ -53,6 +55,8 @@ int expr__find_ids(const char *expr, const char *one,
double expr_id_data__value(const struct expr_id_data *data);
double expr_id_data__source_count(const struct expr_id_data *data);
+double expr_id_data__aggr_nr(const struct expr_id_data *data);
+
double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx);
double expr__has_event(const struct expr_parse_ctx *ctx, bool compute_ids, const char *id);
double expr__strcmp_cpuid_str(const struct expr_parse_ctx *ctx, bool compute_ids, const char *id);
diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l
index a2fc43159ee9..f16ccff278d0 100644
--- a/tools/perf/util/expr.l
+++ b/tools/perf/util/expr.l
@@ -121,6 +121,7 @@ min { return MIN; }
if { return IF; }
else { return ELSE; }
source_count { return SOURCE_COUNT; }
+aggr_nr { return AGGR_NR; }
has_event { return HAS_EVENT; }
strcmp_cpuid_str { return STRCMP_CPUID_STR; }
NaN { return nan_value(yyscanner); }
diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
index e364790babb5..e20f649354cf 100644
--- a/tools/perf/util/expr.y
+++ b/tools/perf/util/expr.y
@@ -41,7 +41,7 @@ int expr_lex(YYSTYPE * yylval_param , void *yyscanner);
} ids;
}
-%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT HAS_EVENT STRCMP_CPUID_STR EXPR_ERROR
+%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT AGGR_NR HAS_EVENT STRCMP_CPUID_STR EXPR_ERROR
%left MIN MAX IF
%left '|'
%left '^'
@@ -87,8 +87,14 @@ static struct ids union_expr(struct ids ids1, struct ids ids2)
return result;
}
+enum expr_id_kind {
+ EXPR_ID_KIND__VALUE,
+ EXPR_ID_KIND__SOURCE_COUNT,
+ EXPR_ID_KIND__AGGR_NR,
+};
+
static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
- bool compute_ids, bool source_count)
+ bool compute_ids, enum expr_id_kind kind)
{
struct ids result;
@@ -101,9 +107,12 @@ static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
result.val = NAN;
if (expr__resolve_id(ctx, id, &data) == 0) {
- result.val = source_count
- ? expr_id_data__source_count(data)
- : expr_id_data__value(data);
+ if (kind == EXPR_ID_KIND__SOURCE_COUNT)
+ result.val = expr_id_data__source_count(data);
+ else if (kind == EXPR_ID_KIND__AGGR_NR)
+ result.val = expr_id_data__aggr_nr(data);
+ else
+ result.val = expr_id_data__value(data);
}
result.ids = NULL;
free(id);
@@ -201,8 +210,9 @@ expr: NUMBER
$$.val = $1;
$$.ids = NULL;
}
-| ID { $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
-| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
+| ID { $$ = handle_id(ctx, $1, compute_ids, EXPR_ID_KIND__VALUE); }
+| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, EXPR_ID_KIND__SOURCE_COUNT); }
+| AGGR_NR '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, EXPR_ID_KIND__AGGR_NR); }
| HAS_EVENT '(' ID ')'
{
$$.val = expr__has_event(ctx, compute_ids, $3);
diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index bc2d44df7baf..e375f6f942be 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -53,6 +53,7 @@ static int prepare_metric(struct perf_stat_config *config,
for (i = 0; metric_events[i]; i++) {
int source_count = 0, tool_aggr_idx;
+ int aggr_nr = 1;
bool is_tool_time =
tool_pmu__is_time_event(config, metric_events[i], &tool_aggr_idx);
struct perf_stat_evsel *ps = metric_events[i]->stats;
@@ -104,13 +105,14 @@ static int prepare_metric(struct perf_stat_config *config,
}
if (!source_count)
source_count = evsel__source_count(metric_events[i]);
+ aggr_nr = aggr->nr ?: 1;
}
}
n = strdup(evsel__metric_id(metric_events[i]));
if (!n)
return -ENOMEM;
- expr__add_id_val_source_count(pctx, n, val, source_count);
+ expr__add_id_val_source_count_aggr_nr(pctx, n, val, source_count, aggr_nr);
}
for (int j = 0; metric_refs && metric_refs[j].metric_name; j++) {
--
2.54.0.669.g59709faab0-goog
^ permalink raw reply [flat|nested] 3+ messages in thread
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Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2026-05-20 17:47 [PATCH 0/2] perf stat: Fix uncore metric scaling across aggregation modes Chun-Tse Shao
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2026-05-20 17:58 [PATCH 0/2] perf stat: Fix uncore metric scaling across aggregation modes Chun-Tse Shao
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