linux/tools/lib/perf/include, branch v6.15

perf cpumap: Reduce cpu size from int to int16_t

2025-02-27T16:47:25Z

Fewer than 32k logical CPUs are currently supported by perf. A cpumap is indexed by an integer (see perf_cpu_map__cpu) yielding a perf_cpu that wraps a 4-byte int for the logical CPU - the wrapping is done deliberately to avoid confusing a logical CPU with an index into a cpumap. Using a 4-byte int within the perf_cpu is larger than required so this patch reduces it to the 2-byte int16_t. For a cpumap containing 16 entries this will reduce the array size from 64 to 32 bytes. For very large servers with lots of logical CPUs the size savings will be greater. Signed-off-by: Ian Rogers Reviewed-by: James Clark Link: https://lore.kernel.org/r/20250210191231.156294-1-irogers@google.com Signed-off-by: Namhyung Kim

libperf cpumap: Remove perf_cpu_map__read()

2024-12-09T20:52:41Z

Function is no longer used and duplicates the parsing logic from perf_cpu_map__new(). Remove to allow simplification. Reviewed-by: Leo Yan Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ben Gainey Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Kyle Meyer Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241206044035.1062032-8-irogers@google.com [ Applied manually to cope with "libperf cpumap: Refactor perf_cpu_map__merge()" ] Signed-off-by: Arnaldo Carvalho de Melo

libperf cpumap: Hide/reduce scope of MAX_NR_CPUS

2024-12-09T20:52:41Z

Avoid redefinition of MAX_NR_CPUS as a global constant, the original definition is tools/perf/perf.h. Reviewed-by: Leo Yan Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ben Gainey Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Kyle Meyer Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241206044035.1062032-4-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf: Increase MAX_NR_CPUS to 4096

2024-12-09T20:52:41Z

Systems have surpassed 2048 CPUs. Increase MAX_NR_CPUS to 4096. Bitmaps declared with MAX_NR_CPUS bits will increase from 256B to 512B, cpus_runtime will increase from 81960B to 163880B, and max_entries will increase from 8192B to 16384B. Reviewed-by: Ian Rogers Reviewed-by: Leo Yan Signed-off-by: Kyle Meyer Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ben Gainey Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20241206044035.1062032-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

libperf cpumap: Refactor perf_cpu_map__merge()

2024-12-09T20:52:41Z

The perf_cpu_map__merge() function has two arguments, 'orig' and 'other'. The function definition might cause confusion as it could give the impression that the CPU maps in the two arguments are copied into a new allocated structure, which is then returned as the result. The purpose of the function is to merge the CPU map 'other' into the CPU map 'orig'. This commit changes the 'orig' argument to a pointer to pointer, so the new result will be updated into 'orig'. The return value is changed to an int type, as an error number or 0 for success. Update callers and tests for the new function definition. Reviewed-by: Adrian Hunter Signed-off-by: Leo Yan Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Ian Rogers Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Link: https://lore.kernel.org/r/20241107125308.41226-2-leo.yan@arm.com Signed-off-by: Arnaldo Carvalho de Melo

tools/perf: Correctly calculate sample period for inherited SAMPLE_READ values

2024-10-02T21:58:03Z

Sample period calculation in deliver_sample_value is updated to calculate the per-thread period delta for events that are inherit + PERF_SAMPLE_READ. When the sampling event has this configuration, the read_format.id is used with the tid from the sample to lookup the storage of the previously accumulated counter total before calculating the delta. All existing valid configurations where read_format.value represents some global value continue to use just the read_format.id to locate the storage of the previously accumulated total. perf_sample_id is modified to support tracking per-thread values, along with the existing global per-id values. In the per-thread case, values are stored in a hash by tid within the perf_sample_id, and are dynamically allocated as the number is not known ahead of time. Signed-off-by: Ben Gainey Cc: james.clark@arm.com Link: https://lore.kernel.org/r/20241001121505.1009685-2-ben.gainey@arm.com Signed-off-by: Namhyung Kim

perf record: Ensure space for lost samples

2024-06-14T03:45:31Z

Previous allocation didn't account for sample ID written after the lost samples event. Switch from malloc/free to a stack allocation. Reported-by: Milian Wolff Closes: https://lore.kernel.org/linux-perf-users/23879991.0LEYPuXRzz@milian-workstation/ Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240611050626.1223155-1-irogers@google.com

libperf cpumap: Add any, empty and min helpers

2024-03-21T13:41:28Z

Additional helpers to better replace perf_cpu_map__has_any_cpu_or_is_empty(). Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andrew Jones Cc: André Almeida Cc: Athira Rajeev Cc: Atish Patra Cc: Changbin Du Cc: Darren Hart Cc: Davidlohr Bueso Cc: Huacai Chen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: K Prateek Nayak Cc: Kajol Jain Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Nick Desaulniers Cc: Paolo Bonzini Cc: Paran Lee Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Suzuki Poulouse Cc: Thomas Gleixner Cc: Will Deacon Cc: Yang Jihong Cc: Yang Li Cc: Yanteng Si Link: https://lore.kernel.org/r/20240202234057.2085863-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

libperf evlist: Avoid out-of-bounds access

2024-02-29T21:57:02Z

Parallel testing appears to show a race between allocating and setting evsel ids. As there is a bounds check on the xyarray it yields a segv like: ``` AddressSanitizer:DEADLYSIGNAL ================================================================= ==484408==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000010 ==484408==The signal is caused by a WRITE memory access. ==484408==Hint: address points to the zero page. #0 0x55cef5d4eff4 in perf_evlist__id_hash tools/lib/perf/evlist.c:256 #1 0x55cef5d4f132 in perf_evlist__id_add tools/lib/perf/evlist.c:274 #2 0x55cef5d4f545 in perf_evlist__id_add_fd tools/lib/perf/evlist.c:315 #3 0x55cef5a1923f in store_evsel_ids util/evsel.c:3130 #4 0x55cef5a19400 in evsel__store_ids util/evsel.c:3147 #5 0x55cef5888204 in __run_perf_stat tools/perf/builtin-stat.c:832 #6 0x55cef5888c06 in run_perf_stat tools/perf/builtin-stat.c:960 #7 0x55cef58932db in cmd_stat tools/perf/builtin-stat.c:2878 ... ``` Avoid this crash by early exiting the perf_evlist__id_add_fd and perf_evlist__id_add is the access is out-of-bounds. Signed-off-by: Ian Rogers Cc: Yang Jihong Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240229070757.796244-1-irogers@google.com

libperf cpumap: Document perf_cpu_map__nr()'s behavior

2023-12-19T00:34:46Z

perf_cpu_map__nr()'s behavior around an empty CPU map is strange as it returns that there is 1 CPU. Changing code that may rely on this behavior is hard, we can at least document the behavior. Reviewed-by: James Clark Signed-off-by: Ian Rogers Acked-by: Adrian Hunter Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andrew Jones Cc: André Almeida Cc: Athira Rajeev Cc: Atish Patra Cc: Changbin Du Cc: Darren Hart Cc: Davidlohr Bueso Cc: Huacai Chen Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: K Prateek Nayak Cc: Kajol Jain Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Nick Desaulniers Cc: Paolo Bonzini Cc: Paran Lee Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Suzuki Poulouse Cc: Thomas Gleixner Cc: Will Deacon Cc: Yang Jihong Cc: Yang Li Cc: Yanteng Si Link: https://lore.kernel.org/r/20231129060211.1890454-15-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo