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4afdc00c37
The control knobs set before loading BPF programs should be declared as
'const volatile' so that it can be optimized by the BPF core.
Committer testing:
root@x1:~# perf lock contention --use-bpf
contended total wait max wait avg wait type caller
5 31.57 us 14.93 us 6.31 us mutex btrfs_delayed_update_inode+0x43
1 16.91 us 16.91 us 16.91 us rwsem:R btrfs_tree_read_lock_nested+0x1b
1 15.13 us 15.13 us 15.13 us spinlock btrfs_getattr+0xd1
1 6.65 us 6.65 us 6.65 us rwsem:R btrfs_tree_read_lock_nested+0x1b
1 4.34 us 4.34 us 4.34 us spinlock process_one_work+0x1a9
root@x1:~#
root@x1:~# perf trace -e bpf --max-events 10 perf lock contention --use-bpf
0.000 ( 0.013 ms): :2948281/2948281 bpf(cmd: 36, uattr: 0x7ffd5f12d730, size: 8) = -1 EOPNOTSUPP (Operation not supported)
0.024 ( 0.120 ms): :2948281/2948281 bpf(cmd: PROG_LOAD, uattr: 0x7ffd5f12d460, size: 148) = 16
0.158 ( 0.034 ms): :2948281/2948281 bpf(cmd: PROG_LOAD, uattr: 0x7ffd5f12d520, size: 148) = 16
26.653 ( 0.154 ms): perf/2948281 bpf(cmd: PROG_LOAD, uattr: 0x7ffd5f12d3d0, size: 148) = 16
26.825 ( 0.014 ms): perf/2948281 bpf(uattr: 0x7ffd5f12d580, size: 80) = 16
87.924 ( 0.038 ms): perf/2948281 bpf(cmd: BTF_LOAD, uattr: 0x7ffd5f12d400, size: 40) = 16
87.988 ( 0.006 ms): perf/2948281 bpf(cmd: BTF_LOAD, uattr: 0x7ffd5f12d470, size: 40) = 16
88.019 ( 0.006 ms): perf/2948281 bpf(cmd: BTF_LOAD, uattr: 0x7ffd5f12d250, size: 40) = 16
88.029 ( 0.172 ms): perf/2948281 bpf(cmd: PROG_LOAD, uattr: 0x7ffd5f12d320, size: 148) = 17
88.217 ( 0.005 ms): perf/2948281 bpf(cmd: BTF_LOAD, uattr: 0x7ffd5f12d4d0, size: 40) = 16
root@x1:~#
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240902200515.2103769-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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| .. | ||
| arch | ||
| bench | ||
| dlfilters | ||
| Documentation | ||
| include/perf | ||
| jvmti | ||
| pmu-events | ||
| python | ||
| scripts | ||
| tests | ||
| trace | ||
| ui | ||
| util | ||
| .gitignore | ||
| Build | ||
| builtin-annotate.c | ||
| builtin-bench.c | ||
| builtin-buildid-cache.c | ||
| builtin-buildid-list.c | ||
| builtin-c2c.c | ||
| builtin-config.c | ||
| builtin-daemon.c | ||
| builtin-data.c | ||
| builtin-diff.c | ||
| builtin-evlist.c | ||
| builtin-ftrace.c | ||
| builtin-help.c | ||
| builtin-inject.c | ||
| builtin-kallsyms.c | ||
| builtin-kmem.c | ||
| builtin-kvm.c | ||
| builtin-kwork.c | ||
| builtin-list.c | ||
| builtin-lock.c | ||
| builtin-mem.c | ||
| builtin-probe.c | ||
| builtin-record.c | ||
| builtin-report.c | ||
| builtin-sched.c | ||
| builtin-script.c | ||
| builtin-stat.c | ||
| builtin-timechart.c | ||
| builtin-top.c | ||
| builtin-trace.c | ||
| builtin-version.c | ||
| builtin.h | ||
| check-headers.sh | ||
| command-list.txt | ||
| CREDITS | ||
| design.txt | ||
| Makefile | ||
| Makefile.config | ||
| Makefile.perf | ||
| MANIFEST | ||
| perf-archive.sh | ||
| perf-completion.sh | ||
| perf-iostat.sh | ||
| perf-read-vdso.c | ||
| perf-sys.h | ||
| perf.c | ||
| perf.h | ||