From: Namhyung Kim Date: Mon, 2 Sep 2024 20:05:12 +0000 (-0700) Subject: perf ftrace latency: Constify control data for BPF X-Git-Tag: v6.12-rc1~109^2~62 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ac5a23b2f2868c54fdd2fc84c1990ebeb1e06188;p=thirdparty%2Fkernel%2Fstable.git perf ftrace latency: Constify control data for BPF 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 ftrace latency --use-bpf -T schedule ^C# DURATION | COUNT | GRAPH | 0 - 1 us | 0 | | 1 - 2 us | 0 | | 2 - 4 us | 0 | | 4 - 8 us | 0 | | 8 - 16 us | 1 | | 16 - 32 us | 5 | | 32 - 64 us | 2 | | 64 - 128 us | 6 | | 128 - 256 us | 7 | | 256 - 512 us | 5 | | 512 - 1024 us | 22 | # | 1 - 2 ms | 36 | ## | 2 - 4 ms | 68 | ##### | 4 - 8 ms | 22 | # | 8 - 16 ms | 91 | ####### | 16 - 32 ms | 11 | | 32 - 64 ms | 26 | ## | 64 - 128 ms | 213 | ################# | 128 - 256 ms | 19 | # | 256 - 512 ms | 14 | # | 512 - 1024 ms | 5 | | 1 - ... s | 8 | | root@x1:~# root@x1:~# perf trace -e bpf perf ftrace latency --use-bpf -T schedule 0.000 ( 0.015 ms): perf/2944525 bpf(cmd: 36, uattr: 0x7ffe80de7b40, size: 8) = -1 EOPNOTSUPP (Operation not supported) 0.025 ( 0.102 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de7870, size: 148) = 8 0.136 ( 0.026 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de7930, size: 148) = 8 0.174 ( 0.026 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de77e0, size: 148) = 8 0.205 ( 0.010 ms): perf/2944525 bpf(uattr: 0x7ffe80de7990, size: 80) = 8 0.227 ( 0.011 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7810, size: 40) = 8 0.244 ( 0.004 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7880, size: 40) = 8 0.257 ( 0.006 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7660, size: 40) = 8 0.265 ( 0.058 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de7730, size: 148) = 9 0.330 ( 0.004 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de78e0, size: 40) = 8 0.337 ( 0.003 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7890, size: 40) = 8 0.343 ( 0.004 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7880, size: 40) = 8 0.349 ( 0.003 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de78b0, size: 40) = 8 0.355 ( 0.004 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7890, size: 40) = 8 0.361 ( 0.003 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de78b0, size: 40) = 8 0.367 ( 0.003 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7880, size: 40) = 8 0.373 ( 0.014 ms): perf/2944525 bpf(cmd: BTF_LOAD, uattr: 0x7ffe80de7a00, size: 40) = 8 0.390 ( 0.358 ms): perf/2944525 bpf(uattr: 0x7ffe80de7950, size: 80) = 9 0.763 ( 0.014 ms): perf/2944525 bpf(uattr: 0x7ffe80de7950, size: 80) = 9 0.783 ( 0.011 ms): perf/2944525 bpf(uattr: 0x7ffe80de7950, size: 80) = 9 0.798 ( 0.017 ms): perf/2944525 bpf(uattr: 0x7ffe80de7950, size: 80) = 9 0.819 ( 0.003 ms): perf/2944525 bpf(uattr: 0x7ffe80de7700, size: 80) = 9 0.824 ( 0.047 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de76c0, size: 148) = 10 0.878 ( 0.008 ms): perf/2944525 bpf(uattr: 0x7ffe80de7950, size: 80) = 9 0.891 ( 0.014 ms): perf/2944525 bpf(cmd: MAP_UPDATE_ELEM, uattr: 0x7ffe80de79e0, size: 32) = 0 0.910 ( 0.103 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de7880, size: 148) = 9 1.016 ( 0.143 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de7880, size: 148) = 10 3.777 ( 0.068 ms): perf/2944525 bpf(cmd: PROG_LOAD, uattr: 0x7ffe80de7570, size: 148) = 12 3.848 ( 0.003 ms): perf/2944525 bpf(cmd: LINK_CREATE, uattr: 0x7ffe80de7550, size: 64) = -1 EBADF (Bad file descriptor) 3.859 ( 0.006 ms): perf/2944525 bpf(cmd: LINK_CREATE, uattr: 0x7ffe80de77c0, size: 64) = 12 6.504 ( 0.010 ms): perf/2944525 bpf(cmd: LINK_CREATE, uattr: 0x7ffe80de77c0, size: 64) = 14 ^C# DURATION | COUNT | GRAPH | 0 - 1 us | 0 | | 1 - 2 us | 0 | | 2 - 4 us | 1 | | 4 - 8 us | 3 | | 8 - 16 us | 3 | | 16 - 32 us | 11 | | 32 - 64 us | 9 | | 64 - 128 us | 17 | | 128 - 256 us | 30 | # | 256 - 512 us | 20 | | 512 - 1024 us | 42 | # | 1 - 2 ms | 151 | ###### | 2 - 4 ms | 106 | #### | 4 - 8 ms | 18 | | 8 - 16 ms | 149 | ###### | 16 - 32 ms | 30 | # | 32 - 64 ms | 17 | | 64 - 128 ms | 360 | ############### | 128 - 256 ms | 52 | ## | 256 - 512 ms | 18 | | 512 - 1024 ms | 28 | # | 1 - ... s | 5 | | root@x1:~# Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Cc: Song Liu Link: https://lore.kernel.org/r/20240902200515.2103769-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/bpf_ftrace.c b/tools/perf/util/bpf_ftrace.c index 7a4297d8fd2ce..06d1c4018407a 100644 --- a/tools/perf/util/bpf_ftrace.c +++ b/tools/perf/util/bpf_ftrace.c @@ -40,13 +40,17 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace) if (ftrace->target.cpu_list) { ncpus = perf_cpu_map__nr(ftrace->evlist->core.user_requested_cpus); bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus); + skel->rodata->has_cpu = 1; } if (target__has_task(&ftrace->target) || target__none(&ftrace->target)) { ntasks = perf_thread_map__nr(ftrace->evlist->core.threads); bpf_map__set_max_entries(skel->maps.task_filter, ntasks); + skel->rodata->has_task = 1; } + skel->rodata->use_nsec = ftrace->use_nsec; + set_max_rlimit(); err = func_latency_bpf__load(skel); @@ -59,7 +63,6 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace) u32 cpu; u8 val = 1; - skel->bss->has_cpu = 1; fd = bpf_map__fd(skel->maps.cpu_filter); for (i = 0; i < ncpus; i++) { @@ -72,7 +75,6 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace) u32 pid; u8 val = 1; - skel->bss->has_task = 1; fd = bpf_map__fd(skel->maps.task_filter); for (i = 0; i < ntasks; i++) { @@ -81,8 +83,6 @@ int perf_ftrace__latency_prepare_bpf(struct perf_ftrace *ftrace) } } - skel->bss->use_nsec = ftrace->use_nsec; - skel->links.func_begin = bpf_program__attach_kprobe(skel->progs.func_begin, false, func->name); if (IS_ERR(skel->links.func_begin)) { diff --git a/tools/perf/util/bpf_skel/func_latency.bpf.c b/tools/perf/util/bpf_skel/func_latency.bpf.c index 9d01e3af74792..f613dc9cb1234 100644 --- a/tools/perf/util/bpf_skel/func_latency.bpf.c +++ b/tools/perf/util/bpf_skel/func_latency.bpf.c @@ -37,9 +37,10 @@ struct { int enabled = 0; -int has_cpu = 0; -int has_task = 0; -int use_nsec = 0; + +const volatile int has_cpu = 0; +const volatile int has_task = 0; +const volatile int use_nsec = 0; SEC("kprobe/func") int BPF_PROG(func_begin)