[PATCH v4 0/3] Add support for a DRM tool like PMU

[PATCH v4 0/3] Add support for a DRM tool like PMU

[Ian Rogers]

DRM clients expose information through usage stats as documented in
Documentation/gpu/drm-usage-stats.rst (available online at
https://docs.kernel.org/gpu/drm-usage-stats.html). Add a tool like
PMU, similar to the hwmon PMU, that exposes DRM information.

v4: Rebase over changes like the auto merge stat to first wildcard PMU
    change and the clean up of tool PMU initialization.

v3: Minor tweak to the test so the skip (exit 2) doesn't trigger the
    trap cleanup.

v2: Add support to only scan hwmon and drm PMUs if the event or PMU
    wildcard can match. Add a test as requested by Namhyung. Add file
    comments.

v1:
https://lore.kernel.org/lkml/20250211071727.364389-1-irogers@google.com/

Ian Rogers (3):
  perf parse-events: Avoid scanning PMUs that can't contain events
  perf drm_pmu: Add a tool like PMU to expose DRM information
  perf tests: Add a DRM PMU test

 tools/perf/tests/shell/drm_pmu.sh |  78 ++++
 tools/perf/util/Build             |   1 +
 tools/perf/util/drm_pmu.c         | 686 ++++++++++++++++++++++++++++++
 tools/perf/util/drm_pmu.h         |  39 ++
 tools/perf/util/evsel.c           |   9 +
 tools/perf/util/parse-events.c    |  33 +-
 tools/perf/util/pmu.c             |  15 +
 tools/perf/util/pmu.h             |   4 +-
 tools/perf/util/pmus.c            | 101 ++++-
 tools/perf/util/pmus.h            |   2 +
 10 files changed, 951 insertions(+), 17 deletions(-)
 create mode 100755 tools/perf/tests/shell/drm_pmu.sh
 create mode 100644 tools/perf/util/drm_pmu.c
 create mode 100644 tools/perf/util/drm_pmu.h

-- 
2.50.0.727.gbf7dc18ff4-goog

[PATCH v4 1/3] perf parse-events: Avoid scanning PMUs that can't contain events

[Ian Rogers]

Add perf_pmus__scan_for_event that only reads sysfs for pmus that
could contain a given event.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/parse-events.c | 33 ++++++++-------
 tools/perf/util/pmus.c         | 77 ++++++++++++++++++++++++++++++++++
 tools/perf/util/pmus.h         |  2 +
 3 files changed, 97 insertions(+), 15 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index d1965a7b97ed..4cd64ffa4fcd 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -490,7 +490,7 @@ int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
 	int ret = 0;
 	struct evsel *first_wildcard_match = NULL;
 
-	while ((pmu = perf_pmus__scan(pmu)) != NULL) {
+	while ((pmu = perf_pmus__scan_for_event(pmu, name)) != NULL) {
 		LIST_HEAD(config_terms);
 		struct perf_event_attr attr;
 
@@ -1681,7 +1681,8 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
 
 	INIT_LIST_HEAD(list);
 
-	while ((pmu = perf_pmus__scan(pmu)) != NULL) {
+	while ((pmu = perf_pmus__scan_for_event(pmu, event_name)) != NULL) {
+
 		if (parse_events__filter_pmu(parse_state, pmu))
 			continue;
 
@@ -1760,19 +1761,21 @@ int parse_events_multi_pmu_add_or_add_pmu(struct parse_events_state *parse_state
 
 	pmu = NULL;
 	/* Failed to add, try wildcard expansion of event_or_pmu as a PMU name. */
-	while ((pmu = perf_pmus__scan(pmu)) != NULL) {
-		if (!parse_events__filter_pmu(parse_state, pmu) &&
-		    perf_pmu__wildcard_match(pmu, event_or_pmu)) {
-			if (!parse_events_add_pmu(parse_state, *listp, pmu,
-						  const_parsed_terms,
-						  first_wildcard_match,
-						  /*alternate_hw_config=*/PERF_COUNT_HW_MAX)) {
-				ok++;
-				parse_state->wild_card_pmus = true;
-			}
-			if (first_wildcard_match == NULL)
-				first_wildcard_match =
-					container_of((*listp)->prev, struct evsel, core.node);
+	while ((pmu = perf_pmus__scan_matching_wildcard(pmu, event_or_pmu)) != NULL) {
+
+		if (parse_events__filter_pmu(parse_state, pmu))
+			continue;
+
+		if (!parse_events_add_pmu(parse_state, *listp, pmu,
+					  const_parsed_terms,
+					  first_wildcard_match,
+					  /*alternate_hw_config=*/PERF_COUNT_HW_MAX)) {
+			ok++;
+			parse_state->wild_card_pmus = true;
+		}
+		if (first_wildcard_match == NULL) {
+			first_wildcard_match =
+				container_of((*listp)->prev, struct evsel, core.node);
 		}
 	}
 	if (ok)
diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index 3bbd26fec78a..e0094f56b8e7 100644
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -19,6 +19,7 @@
 #include "tool_pmu.h"
 #include "print-events.h"
 #include "strbuf.h"
+#include "string2.h"
 
 /*
  * core_pmus:  A PMU belongs to core_pmus if it's name is "cpu" or it's sysfs
@@ -350,6 +351,82 @@ struct perf_pmu *perf_pmus__scan_core(struct perf_pmu *pmu)
 	return NULL;
 }
 
+struct perf_pmu *perf_pmus__scan_for_event(struct perf_pmu *pmu, const char *event)
+{
+	bool use_core_pmus = !pmu || pmu->is_core;
+
+	if (!pmu) {
+		/* Hwmon filename values that aren't used. */
+		enum hwmon_type type;
+		int number;
+		/*
+		 * Core PMUs, other sysfs PMUs and tool PMU can take all event
+		 * types or aren't wother optimizing for.
+		 */
+		unsigned int to_read_pmus =  PERF_TOOL_PMU_TYPE_PE_CORE_MASK |
+			PERF_TOOL_PMU_TYPE_PE_OTHER_MASK |
+			PERF_TOOL_PMU_TYPE_TOOL_MASK;
+
+		/* Could the event be a hwmon event? */
+		if (parse_hwmon_filename(event, &type, &number, /*item=*/NULL, /*alarm=*/NULL))
+			to_read_pmus |= PERF_TOOL_PMU_TYPE_HWMON_MASK;
+
+		pmu_read_sysfs(to_read_pmus);
+		pmu = list_prepare_entry(pmu, &core_pmus, list);
+	}
+	if (use_core_pmus) {
+		list_for_each_entry_continue(pmu, &core_pmus, list)
+			return pmu;
+
+		pmu = NULL;
+		pmu = list_prepare_entry(pmu, &other_pmus, list);
+	}
+	list_for_each_entry_continue(pmu, &other_pmus, list)
+		return pmu;
+	return NULL;
+}
+
+struct perf_pmu *perf_pmus__scan_matching_wildcard(struct perf_pmu *pmu, const char *wildcard)
+{
+	bool use_core_pmus = !pmu || pmu->is_core;
+
+	if (!pmu) {
+		/*
+		 * Core PMUs, other sysfs PMUs and tool PMU can have any name or
+		 * aren't wother optimizing for.
+		 */
+		unsigned int to_read_pmus =  PERF_TOOL_PMU_TYPE_PE_CORE_MASK |
+			PERF_TOOL_PMU_TYPE_PE_OTHER_MASK |
+			PERF_TOOL_PMU_TYPE_TOOL_MASK;
+
+		/*
+		 * Hwmon PMUs have an alias from a sysfs name like hwmon0,
+		 * hwmon1, etc. or have a name of hwmon_<name>. They therefore
+		 * can only have a wildcard match if the wildcard begins with
+		 * "hwmon".
+		 */
+		if (strisglob(wildcard) ||
+		    (strlen(wildcard) >= 5 && strncmp("hwmon", wildcard, 5) == 0))
+			to_read_pmus |= PERF_TOOL_PMU_TYPE_HWMON_MASK;
+
+		pmu_read_sysfs(to_read_pmus);
+		pmu = list_prepare_entry(pmu, &core_pmus, list);
+	}
+	if (use_core_pmus) {
+		list_for_each_entry_continue(pmu, &core_pmus, list) {
+			if (perf_pmu__wildcard_match(pmu, wildcard))
+				return pmu;
+		}
+		pmu = NULL;
+		pmu = list_prepare_entry(pmu, &other_pmus, list);
+	}
+	list_for_each_entry_continue(pmu, &other_pmus, list) {
+		if (perf_pmu__wildcard_match(pmu, wildcard))
+			return pmu;
+	}
+	return NULL;
+}
+
 static struct perf_pmu *perf_pmus__scan_skip_duplicates(struct perf_pmu *pmu)
 {
 	bool use_core_pmus = !pmu || pmu->is_core;
diff --git a/tools/perf/util/pmus.h b/tools/perf/util/pmus.h
index 8def20e615ad..2794d8c3a466 100644
--- a/tools/perf/util/pmus.h
+++ b/tools/perf/util/pmus.h
@@ -19,6 +19,8 @@ struct perf_pmu *perf_pmus__find_by_type(unsigned int type);
 
 struct perf_pmu *perf_pmus__scan(struct perf_pmu *pmu);
 struct perf_pmu *perf_pmus__scan_core(struct perf_pmu *pmu);
+struct perf_pmu *perf_pmus__scan_for_event(struct perf_pmu *pmu, const char *event);
+struct perf_pmu *perf_pmus__scan_matching_wildcard(struct perf_pmu *pmu, const char *wildcard);
 
 const struct perf_pmu *perf_pmus__pmu_for_pmu_filter(const char *str);
 
-- 
2.50.0.727.gbf7dc18ff4-goog

[PATCH v4 2/3] perf drm_pmu: Add a tool like PMU to expose DRM information

[Ian Rogers]

DRM clients expose information through usage stats as documented in
Documentation/gpu/drm-usage-stats.rst (available online at
https://docs.kernel.org/gpu/drm-usage-stats.html). Add a tool like
PMU, similar to the hwmon PMU, that exposes DRM information. For
example on a tigerlake laptop:
```
$ perf list drm

List of pre-defined events (to be used in -e or -M):

drm:
  drm-active-stolen-system0
       [Total memory active in one or more engines. Unit: drm_i915]
  drm-active-system0
       [Total memory active in one or more engines. Unit: drm_i915]
  drm-engine-capacity-video
       [Engine capacity. Unit: drm_i915]
  drm-engine-copy
       [Utilization in ns. Unit: drm_i915]
  drm-engine-render
       [Utilization in ns. Unit: drm_i915]
  drm-engine-video
       [Utilization in ns. Unit: drm_i915]
  drm-engine-video-enhance
       [Utilization in ns. Unit: drm_i915]
  drm-purgeable-stolen-system0
       [Size of resident and purgeable memory bufers. Unit: drm_i915]
  drm-purgeable-system0
       [Size of resident and purgeable memory bufers. Unit: drm_i915]
  drm-resident-stolen-system0
       [Size of resident memory bufers. Unit: drm_i915]
  drm-resident-system0
       [Size of resident memory bufers. Unit: drm_i915]
  drm-shared-stolen-system0
       [Size of shared memory bufers. Unit: drm_i915]
  drm-shared-system0
       [Size of shared memory bufers. Unit: drm_i915]
  drm-total-stolen-system0
       [Size of shared and private memory. Unit: drm_i915]
  drm-total-system0
       [Size of shared and private memory. Unit: drm_i915]
```

System wide data can be gathered:
```
$ perf stat -x, -I 1000 -e drm-active-stolen-system0,drm-active-system0,drm-engine-capacity-video,drm-engine-copy,drm-engine-render,drm-engine-video,drm-engine-video-enhance,drm-purgeable-stolen-system0,drm-purgeable-system0,drm-resident-stolen-system0,drm-resident-system0,drm-shared-stolen-system0,drm-shared-system0,drm-total-stolen-system0,drm-total-system0
1.000904910,0,bytes,drm-active-stolen-system0,1,100.00,,
1.000904910,0,bytes,drm-active-system0,1,100.00,,
1.000904910,36,capacity,drm-engine-capacity-video,1,100.00,,
1.000904910,0,ns,drm-engine-copy,1,100.00,,
1.000904910,1472970566175,ns,drm-engine-render,1,100.00,,
1.000904910,0,ns,drm-engine-video,1,100.00,,
1.000904910,0,ns,drm-engine-video-enhance,1,100.00,,
1.000904910,0,bytes,drm-purgeable-stolen-system0,1,100.00,,
1.000904910,38199296,bytes,drm-purgeable-system0,1,100.00,,
1.000904910,0,bytes,drm-resident-stolen-system0,1,100.00,,
1.000904910,4643196928,bytes,drm-resident-system0,1,100.00,,
1.000904910,0,bytes,drm-shared-stolen-system0,1,100.00,,
1.000904910,1886871552,bytes,drm-shared-system0,1,100.00,,
1.000904910,0,bytes,drm-total-stolen-system0,1,100.00,,
1.000904910,4643196928,bytes,drm-total-system0,1,100.00,,
2.264426839,0,bytes,drm-active-stolen-system0,1,100.00,,
```

Or for a particular process:
```
$ perf stat -x, -I 1000 -e drm-active-stolen-system0,drm-active-system0,drm-engine-capacity-video,drm-engine-copy,drm-engine-render,drm-engine-video,drm-engine-video-enhance,drm-purgeable-stolen-system0,drm-purgeable-system0,drm-resident-stolen-system0,drm-resident-system0,drm-shared-stolen-system0,drm-shared-system0,drm-total-stolen-system0,drm-total-system0 -p 200027
1.001040274,0,bytes,drm-active-stolen-system0,6,100.00,,
1.001040274,0,bytes,drm-active-system0,6,100.00,,
1.001040274,12,capacity,drm-engine-capacity-video,6,100.00,,
1.001040274,0,ns,drm-engine-copy,6,100.00,,
1.001040274,1542300,ns,drm-engine-render,6,100.00,,
1.001040274,0,ns,drm-engine-video,6,100.00,,
1.001040274,0,ns,drm-engine-video-enhance,6,100.00,,
1.001040274,0,bytes,drm-purgeable-stolen-system0,6,100.00,,
1.001040274,13516800,bytes,drm-purgeable-system0,6,100.00,,
1.001040274,0,bytes,drm-resident-stolen-system0,6,100.00,,
1.001040274,27746304,bytes,drm-resident-system0,6,100.00,,
1.001040274,0,bytes,drm-shared-stolen-system0,6,100.00,,
1.001040274,0,bytes,drm-shared-system0,6,100.00,,
1.001040274,0,bytes,drm-total-stolen-system0,6,100.00,,
1.001040274,27746304,bytes,drm-total-system0,6,100.00,,
2.016629075,0,bytes,drm-active-stolen-system0,6,100.00,,
```

As with the hwmon PMU, high numbered PMU types are used to encode
multiple possible "DRM" PMUs. The appropriate fdinfo is found by
scanning /proc and filtering which fdinfos to read with stat. To avoid
some unneeding scanning, events not starting with "drm-" are
ignored. The patch builds on commit 57e13264dcea ("perf pmus:
Restructure pmu_read_sysfs to scan fewer PMUs") and later so that only
if full wild carding is being done, the PMU starts with "drm_" or the
event starts with "drm-" will /proc be scanned. That is there should
be little to no cost in this PMU unless DRM events are requested.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/Build     |   1 +
 tools/perf/util/drm_pmu.c | 686 ++++++++++++++++++++++++++++++++++++++
 tools/perf/util/drm_pmu.h |  39 +++
 tools/perf/util/evsel.c   |   9 +
 tools/perf/util/pmu.c     |  15 +
 tools/perf/util/pmu.h     |   4 +-
 tools/perf/util/pmus.c    |  30 +-
 7 files changed, 779 insertions(+), 5 deletions(-)
 create mode 100644 tools/perf/util/drm_pmu.c
 create mode 100644 tools/perf/util/drm_pmu.h

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 7910d908c814..8a23eb767fb2 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -84,6 +84,7 @@ perf-util-y += pmu.o
 perf-util-y += pmus.o
 perf-util-y += pmu-flex.o
 perf-util-y += pmu-bison.o
+perf-util-y += drm_pmu.o
 perf-util-y += hwmon_pmu.o
 perf-util-y += tool_pmu.o
 perf-util-y += svghelper.o
diff --git a/tools/perf/util/drm_pmu.c b/tools/perf/util/drm_pmu.c
new file mode 100644
index 000000000000..17385a10005b
--- /dev/null
+++ b/tools/perf/util/drm_pmu.c
@@ -0,0 +1,686 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+#include "drm_pmu.h"
+#include "counts.h"
+#include "cpumap.h"
+#include "debug.h"
+#include "evsel.h"
+#include "pmu.h"
+#include <perf/threadmap.h>
+#include <api/fs/fs.h>
+#include <api/io.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <linux/unistd.h>
+#include <linux/kcmp.h>
+#include <linux/zalloc.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+
+enum drm_pmu_unit {
+	DRM_PMU_UNIT_BYTES,
+	DRM_PMU_UNIT_CAPACITY,
+	DRM_PMU_UNIT_CYCLES,
+	DRM_PMU_UNIT_HZ,
+	DRM_PMU_UNIT_NS,
+
+	DRM_PMU_UNIT_MAX,
+};
+
+struct drm_pmu_event {
+	const char *name;
+	const char *desc;
+	enum drm_pmu_unit unit;
+};
+
+struct drm_pmu {
+	struct perf_pmu pmu;
+	struct drm_pmu_event *events;
+	int num_events;
+};
+
+static const char * const drm_pmu_unit_strs[DRM_PMU_UNIT_MAX] = {
+	"bytes",
+	"capacity",
+	"cycles",
+	"hz",
+	"ns",
+};
+
+static const char * const drm_pmu_scale_unit_strs[DRM_PMU_UNIT_MAX] = {
+	"1bytes",
+	"1capacity",
+	"1cycles",
+	"1hz",
+	"1ns",
+};
+
+bool perf_pmu__is_drm(const struct perf_pmu *pmu)
+{
+	return pmu && pmu->type >= PERF_PMU_TYPE_DRM_START &&
+		pmu->type <= PERF_PMU_TYPE_DRM_END;
+}
+
+bool evsel__is_drm(const struct evsel *evsel)
+{
+	return perf_pmu__is_drm(evsel->pmu);
+}
+
+static struct drm_pmu *add_drm_pmu(struct list_head *pmus, char *line, size_t line_len)
+{
+	struct drm_pmu *drm;
+	struct perf_pmu *pmu;
+	const char *name;
+	__u32 max_drm_pmu_type = 0, type;
+	int i = 12;
+
+	if (line[line_len - 1] == '\n')
+		line[line_len - 1] = '\0';
+	while (isspace(line[i]))
+		i++;
+
+	line[--i] = '_';
+	line[--i] = 'm';
+	line[--i] = 'r';
+	line[--i] = 'd';
+	name = &line[i];
+
+	list_for_each_entry(pmu, pmus, list) {
+		if (!perf_pmu__is_drm(pmu))
+			continue;
+		if (pmu->type > max_drm_pmu_type)
+			max_drm_pmu_type = pmu->type;
+		if (!strcmp(pmu->name, name)) {
+			/* PMU already exists. */
+			return NULL;
+		}
+	}
+
+	if (max_drm_pmu_type != 0)
+		type = max_drm_pmu_type + 1;
+	else
+		type = PERF_PMU_TYPE_DRM_START;
+
+	if (type > PERF_PMU_TYPE_DRM_END) {
+		zfree(&drm);
+		pr_err("Unable to encode DRM PMU type for %s\n", name);
+		return NULL;
+	}
+
+	drm = zalloc(sizeof(*drm));
+	if (!drm)
+		return NULL;
+
+	if (perf_pmu__init(&drm->pmu, type, name) != 0) {
+		perf_pmu__delete(&drm->pmu);
+		return NULL;
+	}
+
+	drm->pmu.cpus = perf_cpu_map__new("0");
+	if (!drm->pmu.cpus) {
+		perf_pmu__delete(&drm->pmu);
+		return NULL;
+	}
+	return drm;
+}
+
+
+static bool starts_with(const char *str, const char *prefix)
+{
+	return !strncmp(prefix, str, strlen(prefix));
+}
+
+static int add_event(struct drm_pmu_event **events, int *num_events,
+		     const char *line, enum drm_pmu_unit unit, const char *desc)
+{
+	const char *colon = strchr(line, ':');
+	struct drm_pmu_event *tmp;
+
+	if (!colon)
+		return -EINVAL;
+
+	tmp = reallocarray(*events, *num_events + 1, sizeof(struct drm_pmu_event));
+	if (!tmp)
+		return -ENOMEM;
+	tmp[*num_events].unit = unit;
+	tmp[*num_events].desc = desc;
+	tmp[*num_events].name = strndup(line, colon - line);
+	if (!tmp[*num_events].name)
+		return -ENOMEM;
+	(*num_events)++;
+	*events = tmp;
+	return 0;
+}
+
+static int read_drm_pmus_cb(void *args, int fdinfo_dir_fd, const char *fd_name)
+{
+	struct list_head *pmus = args;
+	char buf[640];
+	struct io io;
+	char *line = NULL;
+	size_t line_len;
+	struct drm_pmu *drm = NULL;
+	struct drm_pmu_event *events = NULL;
+	int num_events = 0;
+
+	io__init(&io, openat(fdinfo_dir_fd, fd_name, O_RDONLY), buf, sizeof(buf));
+	if (io.fd == -1) {
+		/* Failed to open file, ignore. */
+		return 0;
+	}
+
+	while (io__getline(&io, &line, &line_len) > 0) {
+		if (starts_with(line, "drm-driver:")) {
+			drm = add_drm_pmu(pmus, line, line_len);
+			if (!drm)
+				break;
+			continue;
+		}
+		/*
+		 * Note the string matching below is alphabetical, with more
+		 * specific matches appearing before less specific.
+		 */
+		if (starts_with(line, "drm-active-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_BYTES,
+				  "Total memory active in one or more engines");
+			continue;
+		}
+		if (starts_with(line, "drm-cycles-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_CYCLES,
+				"Busy cycles");
+			continue;
+		}
+		if (starts_with(line, "drm-engine-capacity-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_CAPACITY,
+				"Engine capacity");
+			continue;
+		}
+		if (starts_with(line, "drm-engine-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_NS,
+				  "Utilization in ns");
+			continue;
+		}
+		if (starts_with(line, "drm-maxfreq-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_HZ,
+				  "Maximum frequency");
+			continue;
+		}
+		if (starts_with(line, "drm-purgeable-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_BYTES,
+				  "Size of resident and purgeable memory bufers");
+			continue;
+		}
+		if (starts_with(line, "drm-resident-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_BYTES,
+				  "Size of resident memory bufers");
+			continue;
+		}
+		if (starts_with(line, "drm-shared-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_BYTES,
+				  "Size of shared memory bufers");
+			continue;
+		}
+		if (starts_with(line, "drm-total-cycles-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_BYTES,
+				  "Total busy cycles");
+			continue;
+		}
+		if (starts_with(line, "drm-total-")) {
+			add_event(&events, &num_events, line, DRM_PMU_UNIT_BYTES,
+				  "Size of shared and private memory");
+			continue;
+		}
+		if (verbose > 1 && starts_with(line, "drm-") &&
+		    !starts_with(line, "drm-client-id:") &&
+		    !starts_with(line, "drm-pdev:"))
+			pr_debug("Unhandled DRM PMU fdinfo line match '%s'\n", line);
+	}
+	if (drm) {
+		drm->events = events;
+		drm->num_events = num_events;
+		list_add_tail(&drm->pmu.list, pmus);
+	}
+	free(line);
+	if (io.fd != -1)
+		close(io.fd);
+	return 0;
+}
+
+void drm_pmu__exit(struct perf_pmu *pmu)
+{
+	struct drm_pmu *drm = container_of(pmu, struct drm_pmu, pmu);
+
+	free(drm->events);
+}
+
+bool drm_pmu__have_event(const struct perf_pmu *pmu, const char *name)
+{
+	struct drm_pmu *drm = container_of(pmu, struct drm_pmu, pmu);
+
+	if (!starts_with(name, "drm-"))
+		return false;
+
+	for (int i = 0; i < drm->num_events; i++) {
+		if (!strcasecmp(drm->events[i].name, name))
+			return true;
+	}
+	return false;
+}
+
+int drm_pmu__for_each_event(const struct perf_pmu *pmu, void *state, pmu_event_callback cb)
+{
+	struct drm_pmu *drm = container_of(pmu, struct drm_pmu, pmu);
+
+	for (int i = 0; i < drm->num_events; i++) {
+		char encoding_buf[128];
+		struct pmu_event_info info = {
+			.pmu = pmu,
+			.name = drm->events[i].name,
+			.alias = NULL,
+			.scale_unit = drm_pmu_scale_unit_strs[drm->events[i].unit],
+			.desc = drm->events[i].desc,
+			.long_desc = NULL,
+			.encoding_desc = encoding_buf,
+			.topic = "drm",
+			.pmu_name = pmu->name,
+			.event_type_desc = "DRM event",
+		};
+		int ret;
+
+		snprintf(encoding_buf, sizeof(encoding_buf), "%s/config=0x%x/", pmu->name, i);
+
+		ret = cb(state, &info);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+size_t drm_pmu__num_events(const struct perf_pmu *pmu)
+{
+	const struct drm_pmu *drm = container_of(pmu, struct drm_pmu, pmu);
+
+	return drm->num_events;
+}
+
+static int drm_pmu__index_for_event(const struct drm_pmu *drm, const char *name)
+{
+	for (int i = 0; i < drm->num_events; i++) {
+		if (!strcmp(drm->events[i].name, name))
+			return i;
+	}
+	return -1;
+}
+
+static int drm_pmu__config_term(const struct drm_pmu *drm,
+				  struct perf_event_attr *attr,
+				  struct parse_events_term *term,
+				  struct parse_events_error *err)
+{
+	if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER) {
+		int i = drm_pmu__index_for_event(drm, term->config);
+
+		if (i >= 0) {
+			attr->config = i;
+			return 0;
+		}
+	}
+	if (err) {
+		char *err_str;
+
+		parse_events_error__handle(err, term->err_val,
+					asprintf(&err_str,
+						"unexpected drm event term (%s) %s",
+						parse_events__term_type_str(term->type_term),
+						term->config) < 0
+					? strdup("unexpected drm event term")
+					: err_str,
+					NULL);
+	}
+	return -EINVAL;
+}
+
+int drm_pmu__config_terms(const struct perf_pmu *pmu,
+			    struct perf_event_attr *attr,
+			    struct parse_events_terms *terms,
+			    struct parse_events_error *err)
+{
+	struct drm_pmu *drm = container_of(pmu, struct drm_pmu, pmu);
+	struct parse_events_term *term;
+
+	list_for_each_entry(term, &terms->terms, list) {
+		if (drm_pmu__config_term(drm, attr, term, err))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+int drm_pmu__check_alias(const struct perf_pmu *pmu, struct parse_events_terms *terms,
+			 struct perf_pmu_info *info, struct parse_events_error *err)
+{
+	struct drm_pmu *drm = container_of(pmu, struct drm_pmu, pmu);
+	struct parse_events_term *term =
+		list_first_entry(&terms->terms, struct parse_events_term, list);
+
+	if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER) {
+		int i = drm_pmu__index_for_event(drm, term->config);
+
+		if (i >= 0) {
+			info->unit = drm_pmu_unit_strs[drm->events[i].unit];
+			info->scale = 1;
+			return 0;
+		}
+	}
+	if (err) {
+		char *err_str;
+
+		parse_events_error__handle(err, term->err_val,
+					asprintf(&err_str,
+						"unexpected drm event term (%s) %s",
+						parse_events__term_type_str(term->type_term),
+						term->config) < 0
+					? strdup("unexpected drm event term")
+					: err_str,
+					NULL);
+	}
+	return -EINVAL;
+}
+
+struct minor_info {
+	unsigned int *minors;
+	int minors_num, minors_len;
+};
+
+static int for_each_drm_fdinfo_in_dir(int (*cb)(void *args, int fdinfo_dir_fd, const char *fd_name),
+				      void *args, int proc_dir, const char *pid_name,
+				      struct minor_info *minors)
+{
+	char buf[256];
+	DIR *fd_dir;
+	struct dirent *fd_entry;
+	int fd_dir_fd, fdinfo_dir_fd = -1;
+
+
+	scnprintf(buf, sizeof(buf), "%s/fd", pid_name);
+	fd_dir_fd = openat(proc_dir, buf, O_DIRECTORY);
+	if (fd_dir_fd == -1)
+		return 0; /* Presumably lost race to open. */
+	fd_dir = fdopendir(fd_dir_fd);
+	if (!fd_dir) {
+		close(fd_dir_fd);
+		return -ENOMEM;
+	}
+	while ((fd_entry = readdir(fd_dir)) != NULL) {
+		struct stat stat;
+		unsigned int minor;
+		bool is_dup = false;
+		int ret;
+
+		if (fd_entry->d_type != DT_LNK)
+			continue;
+
+		if (fstatat(fd_dir_fd, fd_entry->d_name, &stat, 0) != 0)
+			continue;
+
+		if ((stat.st_mode & S_IFMT) != S_IFCHR || major(stat.st_rdev) != 226)
+			continue;
+
+		minor = minor(stat.st_rdev);
+		for (int i = 0; i < minors->minors_num; i++) {
+			if (minor(stat.st_rdev) == minors->minors[i]) {
+				is_dup = true;
+				break;
+			}
+		}
+		if (is_dup)
+			continue;
+
+		if (minors->minors_num == minors->minors_len) {
+			unsigned int *tmp = reallocarray(minors->minors, minors->minors_len + 4,
+							 sizeof(unsigned int));
+
+			if (tmp) {
+				minors->minors = tmp;
+				minors->minors_len += 4;
+			}
+		}
+		minors->minors[minors->minors_num++] = minor;
+		if (fdinfo_dir_fd == -1) {
+			/* Open fdinfo dir if we have a DRM fd. */
+			scnprintf(buf, sizeof(buf), "%s/fdinfo", pid_name);
+			fdinfo_dir_fd = openat(proc_dir, buf, O_DIRECTORY);
+			if (fdinfo_dir_fd == -1)
+				continue;
+		}
+		ret = cb(args, fdinfo_dir_fd, fd_entry->d_name);
+		if (ret)
+			return ret;
+	}
+	if (fdinfo_dir_fd != -1)
+		close(fdinfo_dir_fd);
+	closedir(fd_dir);
+	return 0;
+}
+
+static int for_each_drm_fdinfo(bool skip_all_duplicates,
+			       int (*cb)(void *args, int fdinfo_dir_fd, const char *fd_name),
+			       void *args)
+{
+	DIR *proc_dir;
+	struct dirent *proc_entry;
+	int ret;
+	/*
+	 * minors maintains an array of DRM minor device numbers seen for a pid,
+	 * or for all pids if skip_all_duplicates is true, so that duplicates
+	 * are ignored.
+	 */
+	struct minor_info minors = {
+		.minors = NULL,
+		.minors_num = 0,
+		.minors_len = 0,
+	};
+
+	proc_dir = opendir(procfs__mountpoint());
+	if (!proc_dir)
+		return 0;
+
+	/* Walk through the /proc directory. */
+	while ((proc_entry = readdir(proc_dir)) != NULL) {
+		if (proc_entry->d_type != DT_DIR ||
+		    !isdigit(proc_entry->d_name[0]))
+			continue;
+		if (!skip_all_duplicates) {
+			/* Reset the seen minor numbers for each pid. */
+			minors.minors_num = 0;
+		}
+		ret = for_each_drm_fdinfo_in_dir(cb, args,
+						 dirfd(proc_dir), proc_entry->d_name,
+						 &minors);
+		if (ret)
+			break;
+	}
+	free(minors.minors);
+	closedir(proc_dir);
+	return ret;
+}
+
+int perf_pmus__read_drm_pmus(struct list_head *pmus)
+{
+	return for_each_drm_fdinfo(/*skip_all_duplicates=*/true, read_drm_pmus_cb, pmus);
+}
+
+int evsel__drm_pmu_open(struct evsel *evsel,
+			struct perf_thread_map *threads,
+			int start_cpu_map_idx, int end_cpu_map_idx)
+{
+	(void)evsel;
+	(void)threads;
+	(void)start_cpu_map_idx;
+	(void)end_cpu_map_idx;
+	return 0;
+}
+
+static uint64_t read_count_and_apply_unit(const char *count_and_unit, enum drm_pmu_unit unit)
+{
+	char *unit_ptr = NULL;
+	uint64_t count = strtoul(count_and_unit, &unit_ptr, 10);
+
+	if (!unit_ptr)
+		return 0;
+
+	while (isblank(*unit_ptr))
+		unit_ptr++;
+
+	switch (unit) {
+	case DRM_PMU_UNIT_BYTES:
+		if (*unit_ptr == '\0')
+			assert(count == 0); /* Generally undocumented, happens for 0. */
+		else if (!strcmp(unit_ptr, "KiB"))
+			count *= 1024;
+		else if (!strcmp(unit_ptr, "MiB"))
+			count *= 1024 * 1024;
+		else
+			pr_err("Unexpected bytes unit '%s'\n", unit_ptr);
+		break;
+	case DRM_PMU_UNIT_CAPACITY:
+		/* No units expected. */
+		break;
+	case DRM_PMU_UNIT_CYCLES:
+		/* No units expected. */
+		break;
+	case DRM_PMU_UNIT_HZ:
+		if (!strcmp(unit_ptr, "Hz"))
+			count *= 1;
+		else if (!strcmp(unit_ptr, "KHz"))
+			count *= 1000;
+		else if (!strcmp(unit_ptr, "MHz"))
+			count *= 1000000;
+		else
+			pr_err("Unexpected hz unit '%s'\n", unit_ptr);
+		break;
+	case DRM_PMU_UNIT_NS:
+		/* Only unit ns expected. */
+		break;
+	case DRM_PMU_UNIT_MAX:
+	default:
+		break;
+	}
+	return count;
+}
+
+static uint64_t read_drm_event(int fdinfo_dir_fd, const char *fd_name,
+			       const char *match, enum drm_pmu_unit unit)
+{
+	char buf[640];
+	struct io io;
+	char *line = NULL;
+	size_t line_len;
+	uint64_t count = 0;
+
+	io__init(&io, openat(fdinfo_dir_fd, fd_name, O_RDONLY), buf, sizeof(buf));
+	if (io.fd == -1) {
+		/* Failed to open file, ignore. */
+		return 0;
+	}
+	while (io__getline(&io, &line, &line_len) > 0) {
+		size_t i = strlen(match);
+
+		if (strncmp(line, match, i))
+			continue;
+		if (line[i] != ':')
+			continue;
+		while (isblank(line[++i]))
+			;
+		if (line[line_len - 1] == '\n')
+			line[line_len - 1] = '\0';
+		count = read_count_and_apply_unit(&line[i], unit);
+		break;
+	}
+	free(line);
+	close(io.fd);
+	return count;
+}
+
+struct read_drm_event_cb_args {
+	const char *match;
+	uint64_t count;
+	enum drm_pmu_unit unit;
+};
+
+static int read_drm_event_cb(void *vargs, int fdinfo_dir_fd, const char *fd_name)
+{
+	struct read_drm_event_cb_args *args = vargs;
+
+	args->count += read_drm_event(fdinfo_dir_fd, fd_name, args->match, args->unit);
+	return 0;
+}
+
+static uint64_t drm_pmu__read_system_wide(struct drm_pmu *drm, struct evsel *evsel)
+{
+	struct read_drm_event_cb_args args = {
+		.count = 0,
+		.match = drm->events[evsel->core.attr.config].name,
+		.unit = drm->events[evsel->core.attr.config].unit,
+	};
+
+	for_each_drm_fdinfo(/*skip_all_duplicates=*/false, read_drm_event_cb, &args);
+	return args.count;
+}
+
+static uint64_t drm_pmu__read_for_pid(struct drm_pmu *drm, struct evsel *evsel, int pid)
+{
+	struct read_drm_event_cb_args args = {
+		.count = 0,
+		.match = drm->events[evsel->core.attr.config].name,
+		.unit = drm->events[evsel->core.attr.config].unit,
+	};
+	struct minor_info minors = {
+		.minors = NULL,
+		.minors_num = 0,
+		.minors_len = 0,
+	};
+	int proc_dir = open(procfs__mountpoint(), O_DIRECTORY);
+	char pid_name[12];
+	int ret;
+
+	if (proc_dir < 0)
+		return 0;
+
+	snprintf(pid_name, sizeof(pid_name), "%d", pid);
+	ret = for_each_drm_fdinfo_in_dir(read_drm_event_cb, &args, proc_dir, pid_name, &minors);
+	free(minors.minors);
+	close(proc_dir);
+	return ret == 0 ? args.count : 0;
+}
+
+int evsel__drm_pmu_read(struct evsel *evsel, int cpu_map_idx, int thread)
+{
+	struct drm_pmu *drm = container_of(evsel->pmu, struct drm_pmu, pmu);
+	struct perf_counts_values *count, *old_count = NULL;
+	int pid = perf_thread_map__pid(evsel->core.threads, thread);
+	uint64_t counter;
+
+	if (pid != -1)
+		counter = drm_pmu__read_for_pid(drm, evsel, pid);
+	else
+		counter = drm_pmu__read_system_wide(drm, evsel);
+
+	if (evsel->prev_raw_counts)
+		old_count = perf_counts(evsel->prev_raw_counts, cpu_map_idx, thread);
+
+	count = perf_counts(evsel->counts, cpu_map_idx, thread);
+	if (old_count) {
+		count->val = old_count->val + counter;
+		count->run = old_count->run + 1;
+		count->ena = old_count->ena + 1;
+	} else {
+		count->val = counter;
+		count->run++;
+		count->ena++;
+	}
+	return 0;
+}
diff --git a/tools/perf/util/drm_pmu.h b/tools/perf/util/drm_pmu.h
new file mode 100644
index 000000000000..e7f366fca8a4
--- /dev/null
+++ b/tools/perf/util/drm_pmu.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __DRM_PMU_H
+#define __DRM_PMU_H
+/*
+ * Linux DRM clients expose information through usage stats as documented in
+ * Documentation/gpu/drm-usage-stats.rst (available online at
+ * https://docs.kernel.org/gpu/drm-usage-stats.html). This is a tool like PMU
+ * that exposes DRM information.
+ */
+
+#include "pmu.h"
+#include <stdbool.h>
+
+struct list_head;
+struct perf_thread_map;
+
+void drm_pmu__exit(struct perf_pmu *pmu);
+bool drm_pmu__have_event(const struct perf_pmu *pmu, const char *name);
+int drm_pmu__for_each_event(const struct perf_pmu *pmu, void *state, pmu_event_callback cb);
+size_t drm_pmu__num_events(const struct perf_pmu *pmu);
+int drm_pmu__config_terms(const struct perf_pmu *pmu,
+			  struct perf_event_attr *attr,
+			  struct parse_events_terms *terms,
+			  struct parse_events_error *err);
+int drm_pmu__check_alias(const struct perf_pmu *pmu, struct parse_events_terms *terms,
+			 struct perf_pmu_info *info, struct parse_events_error *err);
+
+
+bool perf_pmu__is_drm(const struct perf_pmu *pmu);
+bool evsel__is_drm(const struct evsel *evsel);
+
+int perf_pmus__read_drm_pmus(struct list_head *pmus);
+
+int evsel__drm_pmu_open(struct evsel *evsel,
+			struct perf_thread_map *threads,
+			int start_cpu_map_idx, int end_cpu_map_idx);
+int evsel__drm_pmu_read(struct evsel *evsel, int cpu_map_idx, int thread);
+
+#endif /* __DRM_PMU_H */
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index d55482f094bf..9c50c3960487 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -56,6 +56,7 @@
 #include "off_cpu.h"
 #include "pmu.h"
 #include "pmus.h"
+#include "drm_pmu.h"
 #include "hwmon_pmu.h"
 #include "tool_pmu.h"
 #include "rlimit.h"
@@ -1889,6 +1890,9 @@ int evsel__read_counter(struct evsel *evsel, int cpu_map_idx, int thread)
 	if (evsel__is_hwmon(evsel))
 		return evsel__hwmon_pmu_read(evsel, cpu_map_idx, thread);
 
+	if (evsel__is_drm(evsel))
+		return evsel__drm_pmu_read(evsel, cpu_map_idx, thread);
+
 	if (evsel__is_retire_lat(evsel))
 		return evsel__tpebs_read(evsel, cpu_map_idx, thread);
 
@@ -2610,6 +2614,11 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
 					     start_cpu_map_idx,
 					     end_cpu_map_idx);
 	}
+	if (evsel__is_drm(evsel)) {
+		return evsel__drm_pmu_open(evsel, threads,
+					   start_cpu_map_idx,
+					   end_cpu_map_idx);
+	}
 
 	for (idx = start_cpu_map_idx; idx < end_cpu_map_idx; idx++) {
 		cpu = perf_cpu_map__cpu(cpus, idx);
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 609828513f6c..f795883c233f 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -20,6 +20,7 @@
 #include "debug.h"
 #include "evsel.h"
 #include "pmu.h"
+#include "drm_pmu.h"
 #include "hwmon_pmu.h"
 #include "pmus.h"
 #include "tool_pmu.h"
@@ -1627,6 +1628,8 @@ int perf_pmu__config_terms(const struct perf_pmu *pmu,
 
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__config_terms(pmu, attr, terms, err);
+	if (perf_pmu__is_drm(pmu))
+		return drm_pmu__config_terms(pmu, attr, terms, err);
 
 	list_for_each_entry(term, &terms->terms, list) {
 		if (pmu_config_term(pmu, attr, term, terms, zero, apply_hardcoded, err))
@@ -1767,6 +1770,10 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_
 		ret = hwmon_pmu__check_alias(head_terms, info, err);
 		goto out;
 	}
+	if (perf_pmu__is_drm(pmu)) {
+		ret = drm_pmu__check_alias(pmu, head_terms, info, err);
+		goto out;
+	}
 
 	/* Fake PMU doesn't rewrite terms. */
 	if (perf_pmu__is_fake(pmu))
@@ -1949,6 +1956,8 @@ bool perf_pmu__have_event(struct perf_pmu *pmu, const char *name)
 		return false;
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__have_event(pmu, name);
+	if (perf_pmu__is_drm(pmu))
+		return drm_pmu__have_event(pmu, name);
 	if (perf_pmu__find_alias(pmu, name, /*load=*/ true) != NULL)
 		return true;
 	if (pmu->cpu_aliases_added || !pmu->events_table)
@@ -1962,6 +1971,8 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu)
 
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__num_events(pmu);
+	if (perf_pmu__is_drm(pmu))
+		return drm_pmu__num_events(pmu);
 
 	pmu_aliases_parse(pmu);
 	nr = pmu->sysfs_aliases + pmu->sys_json_aliases;
@@ -2030,6 +2041,8 @@ int perf_pmu__for_each_event(struct perf_pmu *pmu, bool skip_duplicate_pmus,
 
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__for_each_event(pmu, state, cb);
+	if (perf_pmu__is_drm(pmu))
+		return drm_pmu__for_each_event(pmu, state, cb);
 
 	strbuf_init(&sb, /*hint=*/ 0);
 	pmu_aliases_parse(pmu);
@@ -2511,6 +2524,8 @@ void perf_pmu__delete(struct perf_pmu *pmu)
 
 	if (perf_pmu__is_hwmon(pmu))
 		hwmon_pmu__exit(pmu);
+	else if (perf_pmu__is_drm(pmu))
+		drm_pmu__exit(pmu);
 
 	perf_pmu__del_formats(&pmu->format);
 	perf_pmu__del_aliases(pmu);
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 71b8636fd07d..a4a08192154c 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -39,7 +39,9 @@ struct perf_pmu_caps {
 
 enum {
 	PERF_PMU_TYPE_PE_START    = 0,
-	PERF_PMU_TYPE_PE_END      = 0xFFFEFFFF,
+	PERF_PMU_TYPE_PE_END      = 0xFFFDFFFF,
+	PERF_PMU_TYPE_DRM_START   = 0xFFFE0000,
+	PERF_PMU_TYPE_DRM_END     = 0xFFFEFFFF,
 	PERF_PMU_TYPE_HWMON_START = 0xFFFF0000,
 	PERF_PMU_TYPE_HWMON_END   = 0xFFFFFFFD,
 	PERF_PMU_TYPE_TOOL = 0xFFFFFFFE,
diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index e0094f56b8e7..81c2ed689db2 100644
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -12,6 +12,7 @@
 #include <unistd.h>
 #include "cpumap.h"
 #include "debug.h"
+#include "drm_pmu.h"
 #include "evsel.h"
 #include "pmus.h"
 #include "pmu.h"
@@ -43,16 +44,19 @@ enum perf_tool_pmu_type {
 	PERF_TOOL_PMU_TYPE_PE_OTHER,
 	PERF_TOOL_PMU_TYPE_TOOL,
 	PERF_TOOL_PMU_TYPE_HWMON,
+	PERF_TOOL_PMU_TYPE_DRM,
 
 #define PERF_TOOL_PMU_TYPE_PE_CORE_MASK (1 << PERF_TOOL_PMU_TYPE_PE_CORE)
 #define PERF_TOOL_PMU_TYPE_PE_OTHER_MASK (1 << PERF_TOOL_PMU_TYPE_PE_OTHER)
 #define PERF_TOOL_PMU_TYPE_TOOL_MASK (1 << PERF_TOOL_PMU_TYPE_TOOL)
 #define PERF_TOOL_PMU_TYPE_HWMON_MASK (1 << PERF_TOOL_PMU_TYPE_HWMON)
+#define PERF_TOOL_PMU_TYPE_DRM_MASK (1 << PERF_TOOL_PMU_TYPE_DRM)
 
 #define PERF_TOOL_PMU_TYPE_ALL_MASK (PERF_TOOL_PMU_TYPE_PE_CORE_MASK |	\
 					PERF_TOOL_PMU_TYPE_PE_OTHER_MASK | \
 					PERF_TOOL_PMU_TYPE_TOOL_MASK |	\
-					PERF_TOOL_PMU_TYPE_HWMON_MASK)
+					PERF_TOOL_PMU_TYPE_HWMON_MASK | \
+					PERF_TOOL_PMU_TYPE_DRM_MASK)
 };
 static unsigned int read_pmu_types;
 
@@ -173,6 +177,8 @@ struct perf_pmu *perf_pmus__find(const char *name)
 	/* Looking up an individual perf event PMU failed, check if a tool PMU should be read. */
 	if (!strncmp(name, "hwmon_", 6))
 		to_read_pmus |= PERF_TOOL_PMU_TYPE_HWMON_MASK;
+	else if (!strncmp(name, "drm_", 4))
+		to_read_pmus |= PERF_TOOL_PMU_TYPE_DRM_MASK;
 	else if (!strcmp(name, "tool"))
 		to_read_pmus |= PERF_TOOL_PMU_TYPE_TOOL_MASK;
 
@@ -273,6 +279,10 @@ static void pmu_read_sysfs(unsigned int to_read_types)
 	    (read_pmu_types & PERF_TOOL_PMU_TYPE_HWMON_MASK) == 0)
 		perf_pmus__read_hwmon_pmus(&other_pmus);
 
+	if ((to_read_types & PERF_TOOL_PMU_TYPE_DRM_MASK) != 0 &&
+	    (read_pmu_types & PERF_TOOL_PMU_TYPE_DRM_MASK) == 0)
+		perf_pmus__read_drm_pmus(&other_pmus);
+
 	list_sort(NULL, &other_pmus, pmus_cmp);
 
 	read_pmu_types |= to_read_types;
@@ -305,6 +315,8 @@ struct perf_pmu *perf_pmus__find_by_type(unsigned int type)
 	if (type >= PERF_PMU_TYPE_PE_START && type <= PERF_PMU_TYPE_PE_END) {
 		to_read_pmus = PERF_TOOL_PMU_TYPE_PE_CORE_MASK |
 			PERF_TOOL_PMU_TYPE_PE_OTHER_MASK;
+	} else if (type >= PERF_PMU_TYPE_DRM_START && type <= PERF_PMU_TYPE_DRM_END) {
+		to_read_pmus = PERF_TOOL_PMU_TYPE_DRM_MASK;
 	} else if (type >= PERF_PMU_TYPE_HWMON_START && type <= PERF_PMU_TYPE_HWMON_END) {
 		to_read_pmus = PERF_TOOL_PMU_TYPE_HWMON_MASK;
 	} else {
@@ -371,6 +383,10 @@ struct perf_pmu *perf_pmus__scan_for_event(struct perf_pmu *pmu, const char *eve
 		if (parse_hwmon_filename(event, &type, &number, /*item=*/NULL, /*alarm=*/NULL))
 			to_read_pmus |= PERF_TOOL_PMU_TYPE_HWMON_MASK;
 
+		/* Could the event be a DRM event? */
+		if (strlen(event) > 4 && strncmp("drm-", event, 4) == 0)
+			to_read_pmus |= PERF_TOOL_PMU_TYPE_DRM_MASK;
+
 		pmu_read_sysfs(to_read_pmus);
 		pmu = list_prepare_entry(pmu, &core_pmus, list);
 	}
@@ -403,11 +419,17 @@ struct perf_pmu *perf_pmus__scan_matching_wildcard(struct perf_pmu *pmu, const c
 		 * Hwmon PMUs have an alias from a sysfs name like hwmon0,
 		 * hwmon1, etc. or have a name of hwmon_<name>. They therefore
 		 * can only have a wildcard match if the wildcard begins with
-		 * "hwmon".
+		 * "hwmon". Similarly drm PMUs must start "drm_", avoid reading
+		 * such events unless the PMU could match.
 		 */
-		if (strisglob(wildcard) ||
-		    (strlen(wildcard) >= 5 && strncmp("hwmon", wildcard, 5) == 0))
+		if (strisglob(wildcard)) {
+			to_read_pmus |= PERF_TOOL_PMU_TYPE_HWMON_MASK |
+				PERF_TOOL_PMU_TYPE_DRM_MASK;
+		} else if (strlen(wildcard) >= 4 && strncmp("drm_", wildcard, 4) == 0) {
+			to_read_pmus |= PERF_TOOL_PMU_TYPE_DRM_MASK;
+		} else if (strlen(wildcard) >= 5 && strncmp("hwmon", wildcard, 5) == 0) {
 			to_read_pmus |= PERF_TOOL_PMU_TYPE_HWMON_MASK;
+		}
 
 		pmu_read_sysfs(to_read_pmus);
 		pmu = list_prepare_entry(pmu, &core_pmus, list);
-- 
2.50.0.727.gbf7dc18ff4-goog

[PATCH v4 3/3] perf tests: Add a DRM PMU test

[Ian Rogers]

The test opens any DRM devices so that the shell has fdinfo files
containing the DRM data. The test then uses perf stat to make sure the
events can be read.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/drm_pmu.sh | 78 +++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100755 tools/perf/tests/shell/drm_pmu.sh

diff --git a/tools/perf/tests/shell/drm_pmu.sh b/tools/perf/tests/shell/drm_pmu.sh
new file mode 100755
index 000000000000..e629fe0e8463
--- /dev/null
+++ b/tools/perf/tests/shell/drm_pmu.sh
@@ -0,0 +1,78 @@
+#!/bin/bash
+# DRM PMU
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+output=$(mktemp /tmp/perf.drm_pmu.XXXXXX.txt)
+
+cleanup() {
+  rm -f "${output}"
+
+  trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+  echo "Unexpected signal in ${FUNCNAME[1]}"
+  cleanup
+  exit 1
+}
+trap trap_cleanup EXIT TERM INT
+
+# Array to store file descriptors and device names
+declare -A device_fds
+
+# Open all devices and store file descriptors. Opening the device will create a
+# /proc/$$/fdinfo file containing the DRM statistics.
+fd_count=3 # Start with file descriptor 3
+for device in /dev/dri/*
+do
+  if [[ ! -c "$device" ]]
+  then
+    continue
+  fi
+  major=$(stat -c "%Hr" "$device")
+  if [[ "$major" != 226 ]]
+  then
+    continue
+  fi
+  echo "Opening $device"
+  eval "exec $fd_count<\"$device\""
+  echo "fdinfo for: $device (FD: $fd_count)"
+  cat "/proc/$$/fdinfo/$fd_count"
+  echo
+  device_fds["$device"]="$fd_count"
+  fd_count=$((fd_count + 1))
+done
+
+if [[ ${#device_fds[@]} -eq 0 ]]
+then
+  echo "No DRM devices found [Skip]"
+  cleanup
+  exit 2
+fi
+
+# For each DRM event
+err=0
+for p in $(perf list --raw-dump drm-)
+do
+  echo -n "Testing perf stat of $p. "
+  perf stat -e "$p" --pid=$$ true > "$output" 2>&1
+  if ! grep -q "$p" "$output"
+  then
+    echo "Missing DRM event in: [Failed]"
+    cat "$output"
+    err=1
+  else
+    echo "[OK]"
+  fi
+done
+
+# Close all file descriptors
+for fd in "${device_fds[@]}"; do
+  eval "exec $fd<&-"
+done
+
+# Finished
+cleanup
+exit $err
-- 
2.50.0.727.gbf7dc18ff4-goog

Re: [PATCH v4 0/3] Add support for a DRM tool like PMU

[Namhyung Kim]

On Tue, 24 Jun 2025 16:18:34 -0700, Ian Rogers wrote:
> DRM clients expose information through usage stats as documented in
> Documentation/gpu/drm-usage-stats.rst (available online at
> https://docs.kernel.org/gpu/drm-usage-stats.html). Add a tool like
> PMU, similar to the hwmon PMU, that exposes DRM information.
> 
> v4: Rebase over changes like the auto merge stat to first wildcard PMU
>     change and the clean up of tool PMU initialization.
> 
> [...]
Applied to perf-tools-next, thanks!

Best regards,
Namhyung