Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [PATCH v3 09/13] perf tools: Introduce bpf-output event | Date | Mon, 30 Nov 2015 07:32:09 +0000 |
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Commit a43eec304259a6c637f4014a6d4767159b6a3aa3 (bpf: introduce bpf_perf_event_output() helper) add a helper to enable BPF program output data to perf ring buffer through a new type of perf event PERF_COUNT_SW_BPF_OUTPUT. This patch enable perf to create perf event of that type. Now perf user can use following cmdline to receive output data from BPF programs:
# ./perf record -a -e evt=bpf-output/no-inherit/ \ -e ./test_bpf_output.c/maps:channel.event=evt/ ls / # ./perf script perf 12927 [004] 355971.129276: 0 evt=bpf-output/no-inherit/: ffffffff811ed5f1 sys_write perf 12927 [004] 355971.129279: 0 evt=bpf-output/no-inherit/: ffffffff811ed5f1 sys_write ...
Test result: # cat ./test_bpf_output.c /************************ BEGIN **************************/ typedef int u32; typedef unsigned long long u64;
enum bpf_map_type { BPF_MAP_TYPE_PERF_EVENT_ARRAY = 4, };
struct bpf_map_def { unsigned int type; unsigned int key_size; unsigned int value_size; unsigned int max_entries; };
#define SEC(NAME) __attribute__((section(NAME), used)) static u64 (*bpf_ktime_get_ns)(void) = (void *)5; static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = (void *)6; static int (*bpf_get_smp_processor_id)(void) = (void *)8; static int (*bpf_perf_event_output)(void *, struct bpf_map_def *, int, void *, unsigned long) = (void *)23;
struct bpf_map_def SEC("maps") channel = { .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, .key_size = sizeof(int), .value_size = sizeof(u32), .max_entries = __NR_CPUS__, };
SEC("func_write=sys_write") int func_write(void *ctx) { struct { u64 ktime; int cpuid; } __attribute__((packed)) output_data; char error_data[] = "Error: failed to output\n";
output_data.cpuid = bpf_get_smp_processor_id(); output_data.ktime = bpf_ktime_get_ns(); int err = bpf_perf_event_output(ctx, &channel, bpf_get_smp_processor_id(), &output_data, sizeof(output_data)); if (err) bpf_trace_printk(error_data, sizeof(error_data)); return 0; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; /************************ END ***************************/
# ./perf record -a -e evt=bpf-output/no-inherit/ \ -e ./test_bpf_output.c/maps:channel.event=evt/ ls / # ./perf script | grep ls ls 4085 [000] 2746114.230215: evt=bpf-output/no-inherit/: ffffffff811ed5f1 sys_write (/lib/modules/4.3.0-rc4+/build/vmlinux) ls 4085 [000] 2746114.230244: evt=bpf-output/no-inherit/: ffffffff811ed5f1 sys_write (/lib/modules/4.3.0-rc4+/build/vmlinux)
Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com --- tools/perf/util/evsel.c | 6 ++++++ tools/perf/util/parse-events.l | 1 + 2 files changed, 7 insertions(+)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 32131fc..4dee8e3 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -224,6 +224,12 @@ struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx) if (evsel != NULL) perf_evsel__init(evsel, attr, idx); + if ((evsel->attr.type == PERF_TYPE_SOFTWARE) && + (evsel->attr.config == PERF_COUNT_SW_BPF_OUTPUT)) { + evsel->attr.sample_type |= PERF_SAMPLE_RAW; + evsel->attr.sample_period = 1; + } + return evsel; } diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l index 8bb3437..27d567f 100644 --- a/tools/perf/util/parse-events.l +++ b/tools/perf/util/parse-events.l @@ -249,6 +249,7 @@ cpu-migrations|migrations { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COU alignment-faults { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_ALIGNMENT_FAULTS); } emulation-faults { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EMULATION_FAULTS); } dummy { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); } +bpf-output { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); } /* * We have to handle the kernel PMU event cycles-ct/cycles-t/mem-loads/mem-stores separately. -- 1.8.3.4
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