kernel.git/tools/perf/util/pmu.h, branch master

perf evlist: Reduce affinity use and move into iterator, fix no affinity

2026-02-10T12:34:44Z

The evlist__for_each_cpu iterator will call sched_setaffitinity when moving between CPUs to avoid IPIs. If only 1 IPI is saved then this may be unprofitable as the delay to get scheduled may be considerable. This may be particularly true if reading an event group in `perf stat` in interval mode. Move the affinity handling completely into the iterator so that a single evlist__use_affinity can determine whether CPU affinities will be used. For `perf record` the change is minimal as the dummy event and the real event will always make the use of affinities the thing to do. In `perf stat`, tool events are ignored and affinities only used if >1 event on the same CPU occur. Determining if affinities are useful is done by evlist__use_affinity which tests per-event whether the event's PMU benefits from affinity use - it is assumed only perf event using PMUs do. Fix a bug where when there are no affinities that the CPU map iterator may reference a CPU not present in the initial evsel. Fix by making the iterator and non-iterator code common. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Andres Freund Cc: Dapeng Mi Cc: Dr. David Alan Gilbert Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Falcon Cc: Thomas Richter Cc: Yang Li Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Special map propagation for tool events that read on 1 CPU

2026-02-10T12:33:28Z

Tool events like duration_time don't need a perf_cpu_map that contains all online CPUs. Having such a perf_cpu_map causes overheads when iterating between events for CPU affinity. During parsing mark events that just read on a single CPU map index as such, then during map propagation set up the evsel's CPUs and thereby the evlists accordingly. The setting cannot be done early in parsing as user CPUs are only fully known when evlist__create_maps is called. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Andres Freund Cc: Dapeng Mi Cc: Dr. David Alan Gilbert Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Falcon Cc: Thomas Richter Cc: Yang Li Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Add a helper to get the value of a config field

2026-01-15T02:15:19Z

This will be used by aux PMUs to read an already written value for configuring their events and for also testing. Its helper perf_pmu__format_unpack() does the opposite of the existing pmu_format_value() so rename that one to perf_pmu__format_pack() so it's clear how they are related. Reviewed-by: Ian Rogers Signed-off-by: James Clark Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Track all user changed config bits

2026-01-15T02:14:54Z

Currently we only track which bits were set by the user in attr->config. But all configN fields should be treated equally as they can all have default and user overridden values. Track them all by making get_config_chgs() generic and calling it once for each config value. Reviewed-by: Ian Rogers Signed-off-by: James Clark Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Support sparse fields in evsel__set_config_if_unset()

2026-01-15T02:14:42Z

Sparse config fields are technically supported although currently unused. field_prep() only works for contiguous bitfields so replace it with pmu_format_value(). pmu_format_value() also takes a bitmap rather than a u64 so replace 'u64 bits' with format->bits. Reviewed-by: Ian Rogers Signed-off-by: James Clark Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo

perf pmu: fix duplicate conditional statement

2025-11-26T17:57:13Z

Remove duplicate check for PERF_PMU_TYPE_DRM_END in perf_pmu__kind. Fixes: f0feb21e0a10 ("perf pmu: Add PMU kind to simplify differentiating") Signed-off-by: Anubhav Shelat Reviewed-by: Ian Rogers Closes: https://lore.kernel.org/linux-perf-users/CA+G8Dh+wLx+FvjjoEkypqvXhbzWEQVpykovzrsHi2_eQjHkzQA@mail.gmail.com/ Signed-off-by: Namhyung Kim

perf tools: Add support for perf_event_attr::config4

2025-11-24T20:20:06Z

perf_event_attr has gained a new field, config4, so add support for it extending the existing configN support. Reviewed-by: Leo Yan Reviewed-by: Ian Rogers Tested-by: Leo Yan Signed-off-by: James Clark Acked-by: Peter Zijlstra (Intel) Signed-off-by: Namhyung Kim

perf pmu: Add PMU kind to simplify differentiating

2025-11-20T01:49:45Z

Rather than perf_pmu__is_xxx calls, and a notion of kind so that a single call can be used. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tools: move perf_pmus__find_core_pmu() prototype to pmus.h

2025-06-26T17:51:31Z

perf_pmus__find_core_pmu() is implemented in util/pmus.c but its prototpye is in util/pmu.h. Move it to util/pmus.h. Suggested-by: Ian Rogers Signed-off-by: Thomas Falcon Reviewed-by: Ian Rogers Link: https://lore.kernel.org/r/20250612163659.1357950-1-thomas.falcon@intel.com Signed-off-by: Namhyung Kim

perf drm_pmu: Add a tool like PMU to expose DRM information

2025-06-25T18:12:35Z

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 Link: https://lore.kernel.org/r/20250624231837.179536-3-irogers@google.com Signed-off-by: Namhyung Kim