kernel/linux.git/tools/perf/util/target.h, branch linux-7.1.y

perf target: Constify simple check functions

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

Allow the target to be const in callers. Signed-off-by: Ian Rogers Tested-by: Thomas Richter Signed-off-by: Namhyung Kim

perf target: Remove uid from target

2025-06-09T18:18:18+00:00

Gathering threads with a uid by scanning /proc is inherently racy leading to perf_event_open failures that quit perf. All users of the functionality now use BPF filters, so remove uid and uid_str from target. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250604174545.2853620-10-irogers@google.com Signed-off-by: Namhyung Kim

perf target: Separate parse_uid into its own function

2025-06-09T18:18:17+00:00

Allow parse_uid to be called without a struct target. Rather than have two errors, remove TARGET_ERRNO__USER_NOT_FOUND and use TARGET_ERRNO__INVALID_UID as the handling is identical. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250604174545.2853620-3-irogers@google.com Signed-off-by: Namhyung Kim

perf stat: Support inherit events during fork() for bperf

2024-11-02T06:31:08+00:00

bperf has a nice ability to share PMUs, but it still does not support inherit events during fork(), resulting in some deviations in its stat results compared with perf. perf stat result: $ ./perf stat -e cycles,instructions -- ./perf test -w sqrtloop Performance counter stats for './perf test -w sqrtloop': 2,316,038,116 cycles 2,859,350,725 instructions 1.009603637 seconds time elapsed 1.004196000 seconds user 0.003950000 seconds sys bperf stat result: $ ./perf stat --bpf-counters -e cycles,instructions -- \ ./perf test -w sqrtloop Performance counter stats for './perf test -w sqrtloop': 18,762,093 cycles 23,487,766 instructions 1.008913769 seconds time elapsed 1.003248000 seconds user 0.004069000 seconds sys In order to support event inheritance, two new bpf programs are added to monitor the fork and exit of tasks respectively. When a task is created, add it to the filter map to enable counting, and reuse the `accum_key` of its parent task to count together with the parent task. When a task exits, remove it from the filter map to disable counting. After support: $ ./perf stat --bpf-counters -e cycles,instructions -- \ ./perf test -w sqrtloop Performance counter stats for './perf test -w sqrtloop': 2,316,252,189 cycles 2,859,946,547 instructions 1.009422314 seconds time elapsed 1.003597000 seconds user 0.004270000 seconds sys Signed-off-by: Tengda Wu Cc: song@kernel.org Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20241021110201.325617-2-wutengda@huaweicloud.com Signed-off-by: Namhyung Kim

perf target: Remove unused hybrid value

2023-05-27T12:38:59+00:00

Previously this was used to modify CPU map propagation, but it is now unnecessary as map propagation ensure core PMUs only have valid PMUs in the CPU map from user requested CPUs. Reviewed-by: Kan Liang Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ali Saidi Cc: Athira Rajeev Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: Huacai Chen Cc: Ingo Molnar Cc: James Clark Cc: Jing Zhang Cc: Jiri Olsa Cc: John Garry Cc: Kajol Jain Cc: Kang Minchul Cc: Leo Yan Cc: Madhavan Srinivasan Cc: Mark Rutland Cc: Mike Leach Cc: Ming Wang Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Rob Herring Cc: Sandipan Das Cc: Sean Christopherson Cc: Suzuki Poulouse Cc: Thomas Richter Cc: Will Deacon Cc: Xing Zhengjun Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230527072210.2900565-11-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Fix counting when initial delay configured

2023-03-02T20:39:03+00:00

When creating counters with initial delay configured, the enable_on_exec field is not set. So we need to enable the counters later. The problem is, when a workload is specified the target__none() is true. So we also need to check stat_config.initial_delay. In this change, we add a new field 'initial_delay' for struct target which could be shared by other subcommands. And define target__enable_on_exec() which returns whether enable_on_exec should be set on normal cases. Before this fix the event is not counted: $ ./perf stat -e instructions -D 100 sleep 2 Events disabled Events enabled Performance counter stats for 'sleep 2': instructions 1.901661124 seconds time elapsed 0.001602000 seconds user 0.000000000 seconds sys After fix it works: $ ./perf stat -e instructions -D 100 sleep 2 Events disabled Events enabled Performance counter stats for 'sleep 2': 404,214 instructions 1.901743475 seconds time elapsed 0.001617000 seconds user 0.000000000 seconds sys Fixes: c587e77e100fa40e ("perf stat: Do not delay the workload with --delay") Signed-off-by: Changbin Du Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Hui Wang Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20230302031146.2801588-2-changbin.du@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Create hybrid flag in target

2021-08-11T19:04:33+00:00

The user may count or collect only on a cpu list via '-C/--cpus' option. Previously cpus for an evsel were retrieved from PMU's sysfs. But if the target cpu list is defined, the retrieved cpus are not kept and the target cpu list is used instead. But for hybrid system, we can't directly use target cpu list. The cpu list may not be available on hybrid pmu (e.g. cpu_core or cpu_atom). So we should not set the 'has_user_cpus' flag for hybrid system. The difficulity is that we can't call perf_pmu__has_hybrid() in evlist.c to check hybrid system otherwise 'perf test python' would be failed (undefined symbol for perf_pmu__has_hybrid). If we add pmu.c to python-ext-sources, too many symbol dependencies are hard to resolve. We use an alternative method by using a new 'hybrid' flag in target for hybrid system checking. Signed-off-by: Jin Yao Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: Ingo Molnar Cc: Jin Yao Cc: Kan Liang Cc: Peter Zijlstra Link: https //lore.kernel.org/r/20210723063433.7318-3-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Introduce config stat.bpf-counter-events

2021-04-29T13:30:58+00:00

Currently, to use BPF to aggregate perf event counters, the user uses --bpf-counters option. Enable "use bpf by default" events with a config option, stat.bpf-counter-events. Events with name in the option will use BPF. This also enables mixed BPF event and regular event in the same sesssion. For example: perf config stat.bpf-counter-events=instructions perf stat -e instructions,cs The second command will use BPF for "instructions" but not "cs". Signed-off-by: Song Liu Cc: Jiri Olsa Cc: Namhyung Kim Cc: Song Liu Link: https://lore.kernel.org/r/20210425214333.1090950-4-song@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Introduce 'bperf' to share hardware PMCs with BPF

2021-03-23T20:46:44+00:00

The perf tool uses performance monitoring counters (PMCs) to monitor system performance. The PMCs are limited hardware resources. For example, Intel CPUs have 3x fixed PMCs and 4x programmable PMCs per cpu. Modern data center systems use these PMCs in many different ways: system level monitoring, (maybe nested) container level monitoring, per process monitoring, profiling (in sample mode), etc. In some cases, there are more active perf_events than available hardware PMCs. To allow all perf_events to have a chance to run, it is necessary to do expensive time multiplexing of events. On the other hand, many monitoring tools count the common metrics (cycles, instructions). It is a waste to have multiple tools create multiple perf_events of "cycles" and occupy multiple PMCs. bperf tries to reduce such wastes by allowing multiple perf_events of "cycles" or "instructions" (at different scopes) to share PMUs. Instead of having each perf-stat session to read its own perf_events, bperf uses BPF programs to read the perf_events and aggregate readings to BPF maps. Then, the perf-stat session(s) reads the values from these BPF maps. Please refer to the comment before the definition of bperf_ops for the description of bperf architecture. bperf is off by default. To enable it, pass --bpf-counters option to perf-stat. bperf uses a BPF hashmap to share information about BPF programs and maps used by bperf. This map is pinned to bpffs. The default path is /sys/fs/bpf/perf_attr_map. The user could change the path with option --bpf-attr-map. Committer testing: # dmesg|grep "Performance Events" -A5 [ 0.225277] Performance Events: Fam17h+ core perfctr, AMD PMU driver. [ 0.225280] ... version: 0 [ 0.225280] ... bit width: 48 [ 0.225281] ... generic registers: 6 [ 0.225281] ... value mask: 0000ffffffffffff [ 0.225281] ... max period: 00007fffffffffff # # for a in $(seq 6) ; do perf stat -a -e cycles,instructions sleep 100000 & done [1] 2436231 [2] 2436232 [3] 2436233 [4] 2436234 [5] 2436235 [6] 2436236 # perf stat -a -e cycles,instructions sleep 0.1 Performance counter stats for 'system wide': 310,326,987 cycles (41.87%) 236,143,290 instructions # 0.76 insn per cycle (41.87%) 0.100800885 seconds time elapsed # We can see that the counters were enabled for this workload 41.87% of the time. Now with --bpf-counters: # for a in $(seq 32) ; do perf stat --bpf-counters -a -e cycles,instructions sleep 100000 & done [1] 2436514 [2] 2436515 [3] 2436516 [4] 2436517 [5] 2436518 [6] 2436519 [7] 2436520 [8] 2436521 [9] 2436522 [10] 2436523 [11] 2436524 [12] 2436525 [13] 2436526 [14] 2436527 [15] 2436528 [16] 2436529 [17] 2436530 [18] 2436531 [19] 2436532 [20] 2436533 [21] 2436534 [22] 2436535 [23] 2436536 [24] 2436537 [25] 2436538 [26] 2436539 [27] 2436540 [28] 2436541 [29] 2436542 [30] 2436543 [31] 2436544 [32] 2436545 # # ls -la /sys/fs/bpf/perf_attr_map -rw-------. 1 root root 0 Mar 23 14:53 /sys/fs/bpf/perf_attr_map # bpftool map | grep bperf | wc -l 64 # # bpftool map | tail 1265: percpu_array name accum_readings flags 0x0 key 4B value 24B max_entries 1 memlock 4096B 1266: hash name filter flags 0x0 key 4B value 4B max_entries 1 memlock 4096B 1267: array name bperf_fo.bss flags 0x400 key 4B value 8B max_entries 1 memlock 4096B btf_id 996 pids perf(2436545) 1268: percpu_array name accum_readings flags 0x0 key 4B value 24B max_entries 1 memlock 4096B 1269: hash name filter flags 0x0 key 4B value 4B max_entries 1 memlock 4096B 1270: array name bperf_fo.bss flags 0x400 key 4B value 8B max_entries 1 memlock 4096B btf_id 997 pids perf(2436541) 1285: array name pid_iter.rodata flags 0x480 key 4B value 4B max_entries 1 memlock 4096B btf_id 1017 frozen pids bpftool(2437504) 1286: array flags 0x0 key 4B value 32B max_entries 1 memlock 4096B # # bpftool map dump id 1268 | tail value (CPU 21): 8f f3 bc ca 00 00 00 00 80 fd 2a d1 4d 00 00 00 80 fd 2a d1 4d 00 00 00 value (CPU 22): 7e d5 64 4d 00 00 00 00 a4 8a 2e ee 4d 00 00 00 a4 8a 2e ee 4d 00 00 00 value (CPU 23): a7 78 3e 06 01 00 00 00 b2 34 94 f6 4d 00 00 00 b2 34 94 f6 4d 00 00 00 Found 1 element # bpftool map dump id 1268 | tail value (CPU 21): c6 8b d9 ca 00 00 00 00 20 c6 fc 83 4e 00 00 00 20 c6 fc 83 4e 00 00 00 value (CPU 22): 9c b4 d2 4d 00 00 00 00 3e 0c df 89 4e 00 00 00 3e 0c df 89 4e 00 00 00 value (CPU 23): 18 43 66 06 01 00 00 00 5b 69 ed 83 4e 00 00 00 5b 69 ed 83 4e 00 00 00 Found 1 element # bpftool map dump id 1268 | tail value (CPU 21): f2 6e db ca 00 00 00 00 92 67 4c ba 4e 00 00 00 92 67 4c ba 4e 00 00 00 value (CPU 22): dc 8e e1 4d 00 00 00 00 d9 32 7a c5 4e 00 00 00 d9 32 7a c5 4e 00 00 00 value (CPU 23): bd 2b 73 06 01 00 00 00 7c 73 87 bf 4e 00 00 00 7c 73 87 bf 4e 00 00 00 Found 1 element # # perf stat --bpf-counters -a -e cycles,instructions sleep 0.1 Performance counter stats for 'system wide': 119,410,122 cycles 152,105,479 instructions # 1.27 insn per cycle 0.101395093 seconds time elapsed # See? We had the counters enabled all the time. Signed-off-by: Song Liu Reviewed-by: Jiri Olsa Acked-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: kernel-team@fb.com Link: http://lore.kernel.org/lkml/20210316211837.910506-2-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Enable counting events for BPF programs

2021-01-20T17:25:28+00:00

Introduce 'perf stat -b' option, which counts events for BPF programs, like: [root@localhost ~]# ~/perf stat -e ref-cycles,cycles -b 254 -I 1000 1.487903822 115,200 ref-cycles 1.487903822 86,012 cycles 2.489147029 80,560 ref-cycles 2.489147029 73,784 cycles 3.490341825 60,720 ref-cycles 3.490341825 37,797 cycles 4.491540887 37,120 ref-cycles 4.491540887 31,963 cycles The example above counts 'cycles' and 'ref-cycles' of BPF program of id 254. This is similar to bpftool-prog-profile command, but more flexible. 'perf stat -b' creates per-cpu perf_event and loads fentry/fexit BPF programs (monitor-progs) to the target BPF program (target-prog). The monitor-progs read perf_event before and after the target-prog, and aggregate the difference in a BPF map. Then the user space reads data from these maps. A new 'struct bpf_counter' is introduced to provide a common interface that uses BPF programs/maps to count perf events. Committer notes: Removed all but bpf_counter.h includes from evsel.h, not needed at all. Also BPF map lookups for PERCPU_ARRAYs need to have as its value receive buffer passed to the kernel libbpf_num_possible_cpus() entries, not evsel__nr_cpus(evsel), as the former uses /sys/devices/system/cpu/possible while the later uses /sys/devices/system/cpu/online, which may be less than the 'possible' number making the bpf map lookup overwrite memory and cause hard to debug memory corruption. We need to continue using evsel__nr_cpus(evsel) when accessing the perf_counts array tho, not to overwrite another are of memory :-) Signed-off-by: Song Liu Tested-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/lkml/20210120163031.GU12699@kernel.org/ Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Mark Rutland Cc: Peter Zijlstra Cc: kernel-team@fb.com Link: http://lore.kernel.org/lkml/20201229214214.3413833-4-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo