kernel/linux.git/tools/perf/builtin-record.c, branch v7.1

perf data: Clean up use_stdio and structures

2026-04-09T02:21:17+00:00

use_stdio was associated with struct perf_data and not perf_data_file meaning there was implicit use of fd rather than fptr that may not be safe. For example, in perf_data_file__write. Reorganize perf_data_file to better abstract use_stdio, add kernel-doc and more consistently use perf_data__ accessors so that use_stdio is better respected. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tools: Use calloc() where applicable

2026-04-09T02:21:05+00:00

Instead of using zalloc(nr_entries * sizeof_entry) that is what calloc() does. In some places where linux/zalloc.h isn't needed, remove it, add when needed and was getting it indirectly. Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim

libperf cpumap: Make index and nr types unsigned

2026-04-01T21:50:53+00:00

The index into the cpumap array and the number of entries within the array can never be negative, so let's make them unsigned. This is prompted by reports that gcc 13 with -O6 is giving a alloc-size-larger-than errors. The change makes the cpumap changes and then updates the declaration of index variables throughout perf and libperf to be unsigned. The two things are hard to separate as compiler warnings about mixing signed and unsigned types breaks the build. Reported-by: Chingbin Li Closes: https://lore.kernel.org/lkml/20260212025127.841090-1-liqb365@163.com/ Tested-by: Chingbin Li Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf evlist: Improve default event for s390

2026-03-19T21:42:46+00:00

Frame pointer callchains are not supported on s390 and dwarf callchains are only supported on software events. Switch the default event from the hardware 'cycles' event to the software 'cpu-clock' or 'task-clock' on s390 if callchains are enabled. Move some of the target initialization earlier in builtin-top and builtin-record, so it is ready for use by evlist__new_default. If frame pointer callchains are requested on s390 show a warning. Modify the '-g' option of `perf top` and `perf record` to default to dwarf callchains on s390. Signed-off-by: Ian Rogers Tested-by: Thomas Richter Signed-off-by: Namhyung Kim

perf callchain: Refactor callchain option parsing

2026-03-19T21:42:46+00:00

record_opts__parse_callchain is shared by builtin-record and builtin-trace, it is declared in callchain.h. Move the declaration to callchain.c for consistency with the header. In other cases make the option callback a small static stub that then calls into callchain.c. Make the no argument '-g' callchain option just a short-cut for '--call-graph fp' so that there is consistency in how the arguments are handled. This requires the const char* string to be strdup-ed in __parse_callchain_report_opt. For consistency also make parse_callchain_record use strdup and remove some unnecessary casts. Also, be more explicit about the '-g' behavior if there is a .perfconfig file setting. Signed-off-by: Ian Rogers Tested-by: Thomas Richter Signed-off-by: Namhyung Kim

perf record: Remove unused cpu-set-sched.h

2026-03-13T21:26:28+00:00

Header file declares unused macros, so remove. Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf record: Make logs more readable for event open failures

2026-02-06T14:53:10+00:00

Since commit ee27476fa3004f83 ("perf record: Skip don't fail for events that don't open"), if a user does not have permission to access a PMU event, perf reports: perf record -e cs_etm// -C 3 -- ls Error: Failure to open event 'cs_etm//u' on PMU 'cs_etm' which will be removed. No fallback found for 'cs_etm//u' for error 13 Error: Failure to open event 'dummy:u' on PMU 'software' which will be removed. No fallback found for 'dummy:u' for error 13 Error: Failure to open any events for recording. The log is not very helpful, as no clear indication of what "error 13" means or how to address the issue. This commit restores evsel__open_strerror() to generate a readable error message and print it out: perf record -e cs_etm// -C 3 -- ls Error: Failure to open event 'cs_etm//' on PMU 'cs_etm' which will be removed. Access to performance monitoring and observability operations is limited. Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open access to performance monitoring and observability operations for processes without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability. More information can be found at 'Perf events and tool security' document: https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html perf_event_paranoid setting is 1: -1: Allow use of (almost) all events by all users Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >= 0: Disallow raw and ftrace function tracepoint access >= 1: Disallow CPU event access >= 2: Disallow kernel profiling To make the adjusted perf_event_paranoid setting permanent preserve it in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = ) Error: Failure to open event 'dummy:u' on PMU 'software' which will be removed. Access to performance monitoring and observability operations is limited. Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open access to performance monitoring and observability operations for processes without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability. More information can be found at 'Perf events and tool security' document: https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html perf_event_paranoid setting is 1: -1: Allow use of (almost) all events by all users Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >= 0: Disallow raw and ftrace function tracepoint access >= 1: Disallow CPU event access >= 2: Disallow kernel profiling To make the adjusted perf_event_paranoid setting permanent preserve it in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = ) Error: Failure to open any events for recording. Reviewed-by: Ian Rogers Signed-off-by: Leo Yan Cc: Adrian Hunter Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Signed-off-by: Arnaldo Carvalho de Melo

perf record: Disable inline frames when marking build IDs

2026-01-20T15:56:19+00:00

Marking DSOs doesn't need inline frames traversing as the inline frames are all part of the same DSO. Disable to improve performance and also to avoid potential issues with dwarf information. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Albert Ou Cc: Alexandre Ghiti Cc: Andi Kleen Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Guo Ren Cc: Haibo Xu Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Mark Wielaard Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Thomas Falcon Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Switch printf("...%s", strerror(errno)) to printf("...%m")

2026-01-14T20:22:50+00:00

strerror() has thread safety issues, strerror_r() requires stack allocated buffers. Code in perf has already been using the "%m" formatting flag that is a widely support glibc extension to print the current errno's description. Expand the usage of this formatting flag and remove usage of strerror()/strerror_r(). Signed-off-by: Ian Rogers Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Blake Jones Cc: Chun-Tse Shao Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Haibo Xu Cc: Howard Chu Cc: Ingo Molnar Cc: Jiri Olsa Cc: Leo Yan Cc: Peter Zijlstra Cc: Stephen Brennan Cc: Thomas Falcon Cc: Yunseong Kim Cc: Zhongqiu Han Signed-off-by: Arnaldo Carvalho de Melo

perf record: Split --data-mmap option

2025-12-17T12:30:37+00:00

Currently -d/--data option controls both PERF_SAMPLE_ADDR bit and perf_event_attr.mmap_data flag. Separate them using new --data-mmap option to support recording only one of them. For data-type profiling, data MMAP is unnecessary but it wastes a lot of space in the ring buffer and data file. Committer testing: On an idle system: root@x1:~# perf record -d -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 5.672 MB perf.data (1075 samples) ] root@x1:~# ls -la perf.data -rw-------. 1 root root 5982480 Dec 16 15:34 perf.data root@x1:~# perf evlist -v cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ADDR|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1 cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ADDR|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1 dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 144, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|ADDR|CPU|IDENTIFIER|DATA_SRC, read_format: ID|LOST, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, mmap_data: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1 root@x1:~# Now with just --data-mmap we will not save that much, as only DATA_SRC will not be enabled in sample_type: root@x1:~# perf record --data-mmap -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 5.576 MB perf.data (716 samples) ] root@x1:~# ls -la perf.data -rw-------. 1 root root 5880112 Dec 16 15:37 perf.data root@x1:~# perf evlist -v cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1 cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1 dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 144, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER, read_format: ID|LOST, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, mmap_data: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1 root@x1:~# To complete, just with DATA_SRC, no mmap_data: root@x1:~# perf record --sample-mem-info -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 1.407 MB perf.data (1311 samples) ] root@x1:~# ls -la perf.data -rw-------. 1 root root 1509224 Dec 16 15:40 perf.data root@x1:~# perf evlist -v cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1 cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1 dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 144, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER|DATA_SRC, read_format: ID|LOST, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1 root@x1:~# Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo