kernel/linux.git/tools/perf/util/stat-display.c, branch v6.19.11

perf stat: Ensure metrics are displayed even with failed events

2026-03-04T12:19:29+00:00

[ Upstream commit bb5a920b9099127915706fdd23eb540c9a69c338 ] Currently, `perf stat` skips or hides metrics when the underlying hardware events cannot be counted (e.g., due to insufficient permissions or unsupported events). In `--metric-only` mode, this often results in missing columns or blank spaces, making the output difficult to parse. Modify the logic to ensure metrics are consistently displayed by propagating NAN (Not a Number) through the expression evaluator. Specifically: 1. Update `prepare_metric()` in stat-shadow.c to treat uncounted events (where `run == 0`) as NAN. This leverages the existing math in expr.y to propagate NAN through metric expressions. 2. Remove the early return in the display logic's `printout()` function that was previously skipping metrics in `--metric-only` mode for failed events. l 3. Simplify `perf_stat__skip_metric_event()` to no longer depend on event runtime. Tested: 1. `perf all metrics test` did not crash while paranoid is 2. 2. Multiple combinations with `CPUs_utilized` while paranoid is 2. $ ./perf stat -M CPUs_utilized -a -- sleep 1 Performance counter stats for 'system wide': msec cpu-clock:u # nan CPUs CPUs_utilized 1,006,356,120 duration_time 1.004375550 seconds time elapsed $ ./perf stat -M CPUs_utilized -a -j -- sleep 1 {"counter-value" : "", "unit" : "msec", "event" : "cpu-clock:u", "event-runtime" : 0, "pcnt-running" : 100.00, "metric-value" : "nan", "metric-unit" : "CPUs CPUs_utilized"} {"counter-value" : "1006642462.000000", "unit" : "", "event" : "duration_time", "event-runtime" : 1, "pcnt-running" : 100.00} $ ./perf stat -M CPUs_utilized -a --metric-only -- sleep 1 Performance counter stats for 'system wide': CPUs CPUs_utilized nan 1.004424652 seconds time elapsed $ ./perf stat -M CPUs_utilized -a --metric-only -j -- sleep 1 {"CPUs CPUs_utilized" : "none"} Reviewed-by: Ian Rogers Signed-off-by: Chun-Tse Shao Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Yang Li Signed-off-by: Arnaldo Carvalho de Melo Stable-dep-of: 63b320aaac08 ("perf stat-shadow: In prepare_metric fix guard on reading NULL perf_stat_evsel") Signed-off-by: Sasha Levin

perf stat: Display metric-only for 0 counters

2025-11-18T01:31:59+00:00

0 counters may occur in hypervisor settings but metric-only output is always expected. This resolves an issue in the "perf stat STD output linter" test. Signed-off-by: Ian Rogers Tested-by: Thomas Falcon Signed-off-by: Namhyung Kim

perf stat: Align metric output without events

2025-11-12T01:00:31+00:00

One of my concern in the perf stat output was the alignment in the metrics and shadow stats. I think it missed to calculate the basic output length using COUNTS_LEN and EVNAME_LEN but missed to add the unit length like "msec" and surround 2 spaces. I'm not sure why it's not printed below though. But anyway, now it shows correctly aligned metric output. $ perf stat true Performance counter stats for 'true': 859,772 task-clock # 0.395 CPUs utilized 0 context-switches # 0.000 /sec 0 cpu-migrations # 0.000 /sec 56 page-faults # 65.134 K/sec 1,075,022 instructions # 0.86 insn per cycle 1,255,911 cycles # 1.461 GHz 220,573 branches # 256.548 M/sec 7,381 branch-misses # 3.35% of all branches TopdownL1 # 19.2 % tma_retiring # 28.6 % tma_backend_bound # 9.5 % tma_bad_speculation # 42.6 % tma_frontend_bound 0.002174871 seconds time elapsed ^ | 0.002154000 seconds user | 0.000000000 seconds sys here Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim

perf stat: Remove "unit" workarounds for metric-only

2025-11-12T00:48:35+00:00

Remove code that tested the "unit" as in KB/sec for certain hard coded metric values and did workarounds. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf stat: Remove hard coded shadow metrics

2025-11-12T00:48:35+00:00

Now that the metrics are encoded in common json the hard coded printing means the metrics are shown twice. Remove the hard coded version. This means that when specifying events, and those events correspond to a hard coded metric, the metric will no longer be displayed. The metric will be displayed if the metric is requested. Due to the adhoc printing in the previous approach it was often found frustrating, the new approach avoids this. The default perf stat output on an alderlake now looks like: ``` $ perf stat -a -- sleep 1 Performance counter stats for 'system wide': 19,697 context-switches # nan cs/sec cs_per_second TopdownL1 (cpu_core) # 10.7 % tma_bad_speculation # 24.9 % tma_frontend_bound TopdownL1 (cpu_core) # 34.3 % tma_backend_bound # 30.1 % tma_retiring 6,593 page-faults # nan faults/sec page_faults_per_second 729,065,658 cpu_atom/cpu-cycles/ # nan GHz cycles_frequency (49.79%) 1,605,131,101 cpu_core/cpu-cycles/ # nan GHz cycles_frequency # 19.7 % tma_bad_speculation # 14.2 % tma_retiring (50.14%) # 37.3 % tma_frontend_bound (50.31%) 87,302,268 cpu_atom/branches/ # nan M/sec branch_frequency (60.27%) 512,046,956 cpu_core/branches/ # nan M/sec branch_frequency 1,111 cpu-migrations # nan migrations/sec migrations_per_second # 28.8 % tma_backend_bound (60.26%) 0.00 msec cpu-clock # 0.0 CPUs CPUs_utilized 392,509,323 cpu_atom/instructions/ # 0.6 instructions insn_per_cycle (60.19%) 2,990,369,310 cpu_core/instructions/ # 1.9 instructions insn_per_cycle 3,493,478 cpu_atom/branch-misses/ # 5.9 % branch_miss_rate (49.69%) 7,297,531 cpu_core/branch-misses/ # 1.4 % branch_miss_rate 1.006621701 seconds time elapsed ``` Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf jevents: Add metric DefaultShowEvents

2025-11-12T00:48:35+00:00

Some Default group metrics require their events showing for consistency with perf's previous behavior. Add a flag to indicate when this is the case and use it in stat-display. As events are coming from Default metrics remove that default hardware and software events from perf stat. Following this change the default perf stat output on an alderlake looks like: ``` $ perf stat -a -- sleep 1 Performance counter stats for 'system wide': 20,550 context-switches # nan cs/sec cs_per_second TopdownL1 (cpu_core) # 9.0 % tma_bad_speculation # 28.1 % tma_frontend_bound TopdownL1 (cpu_core) # 29.2 % tma_backend_bound # 33.7 % tma_retiring 6,685 page-faults # nan faults/sec page_faults_per_second 790,091,064 cpu_atom/cpu-cycles/ # nan GHz cycles_frequency (49.83%) 2,563,918,366 cpu_core/cpu-cycles/ # nan GHz cycles_frequency # 12.3 % tma_bad_speculation # 14.5 % tma_retiring (50.20%) # 33.8 % tma_frontend_bound (50.24%) 76,390,322 cpu_atom/branches/ # nan M/sec branch_frequency (60.20%) 1,015,173,047 cpu_core/branches/ # nan M/sec branch_frequency 1,325 cpu-migrations # nan migrations/sec migrations_per_second # 39.3 % tma_backend_bound (60.17%) 0.00 msec cpu-clock # 0.000 CPUs utilized # 0.0 CPUs CPUs_utilized 554,347,072 cpu_atom/instructions/ # 0.64 insn per cycle # 0.6 instructions insn_per_cycle (60.14%) 5,228,931,991 cpu_core/instructions/ # 2.04 insn per cycle # 2.0 instructions insn_per_cycle 4,308,874 cpu_atom/branch-misses/ # 5.65% of all branches # 5.6 % branch_miss_rate (49.76%) 9,890,606 cpu_core/branch-misses/ # 0.97% of all branches # 1.0 % branch_miss_rate 1.005477803 seconds time elapsed ``` Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf stat: Move metric list from config to evlist

2025-07-11T19:36:40+00:00

The rblist of metric_event that then have a list of associated metric_expr is moved out of the stat_config and into the evlist. This is done as part of refactoring things for python, having the state split in two places complicates that implementation. The evlist is doing the harder work of enabling and disabling events, the metrics are needed to compute a value and it doesn't seem unreasonable to hang them from the evlist. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250710235126.1086011-7-irogers@google.com Signed-off-by: Namhyung Kim

perf stat: Fix uncore aggregation number

2025-06-27T23:14:10+00:00

Follow up: lore.kernel.org/CAP-5=fVDF4-qYL1Lm7efgiHk7X=_nw_nEFMBZFMcsnOOJgX4Kg@mail.gmail.com/ The patch adds unit aggregation during evsel merge the aggregated uncore counters. Change the name of the column to `ctrs` and `counters` for json mode. Tested on a 2-socket machine with SNC3, uncore_imc_[0-11] and cpumask="0,120" Before: perf stat -e clockticks -I 1000 --per-socket # time socket cpus counts unit events 1.001085024 S0 1 9615386315 clockticks 1.001085024 S1 1 9614287448 clockticks perf stat -e clockticks -I 1000 --per-node # time node cpus counts unit events 1.001029867 N0 1 3205726984 clockticks 1.001029867 N1 1 3205444421 clockticks 1.001029867 N2 1 3205234018 clockticks 1.001029867 N3 1 3205224660 clockticks 1.001029867 N4 1 3205207213 clockticks 1.001029867 N5 1 3205528246 clockticks After: perf stat -e clockticks -I 1000 --per-socket # time socket ctrs counts unit events 1.001026071 S0 12 9619677996 clockticks 1.001026071 S1 12 9618612614 clockticks perf stat -e clockticks -I 1000 --per-node # time node ctrs counts unit events 1.001027449 N0 4 3207251859 clockticks 1.001027449 N1 4 3207315930 clockticks 1.001027449 N2 4 3206981828 clockticks 1.001027449 N3 4 3206566126 clockticks 1.001027449 N4 4 3206032609 clockticks 1.001027449 N5 4 3205651355 clockticks Tested with JSON output linter: perf test "perf stat JSON output linter" 94: perf stat JSON output linter : Ok Suggested-by: Ian Rogers Reviewed-by: Ian Rogers Signed-off-by: Chun-Tse Shao Link: https://lore.kernel.org/r/20250627201818.479421-1-ctshao@google.com Signed-off-by: Namhyung Kim

perf parse-events: Use wildcard processing to set an event to merge into

2025-05-14T12:36:24+00:00

The merge stat code fails for uncore events if they are repeated twice, for example `perf stat -e clockticks,clockticks -I 1000` as the counts of the second set of uncore events will be merged into the first counter. Reimplement the logic to have a first_wildcard_match so that merged later events correctly merge into the first wildcard event that they will be aggregated into. Signed-off-by: Ian Rogers Tested-by: Chun-Tse Shao Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Dr. David Alan Gilbert Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Levi Yun Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Weilin Wang Link: https://lore.kernel.org/r/20250513215401.2315949-3-ctshao@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Make uniquifying counter names consistent

2025-05-14T12:36:21+00:00

'perf stat' has different uniquification logic to 'perf record' and perf top. In the case of perf record and 'perf top' all hybrid event names are uniquified. 'perf stat' is more disciplined respecting name config terms, libpfm4 events, etc. 'perf stat' will uniquify hybrid events and the non-core PMU cases shouldn't apply to perf record or 'perf top'. For consistency, remove the uniquification for 'perf record' and 'perf top' and reuse the 'perf stat' uniquification, making the code more globally visible for this. Fix the detection of cross-PMU for disabling uniquify by correctly setting last_pmu. When setting uniquify on an evsel, make sure the PMUs between the 2 considered events differ otherwise the uniquify isn't adding value. Signed-off-by: Ian Rogers Tested-by: Chun-Tse Shao Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Dr. David Alan Gilbert Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Levi Yun Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Weilin Wang Link: https://lore.kernel.org/r/20250513215401.2315949-2-ctshao@google.com Signed-off-by: Arnaldo Carvalho de Melo