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| author | Yonghong Song <yhs@fb.com> | 2017-10-05 09:19:23 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-07 23:05:57 +0100 |
| commit | 81b9cf8028a17bdbdaa0da80b735b32150d4e89e (patch) | |
| tree | b5ec33cc6476e31c8e30c6623e635c6b75be80ae /samples/bpf/trace_event_kern.c | |
| parent | 4bebdc7a85aa400c0222b5329861e4ad9252f1e5 (diff) | |
| download | lwn-81b9cf8028a17bdbdaa0da80b735b32150d4e89e.tar.gz lwn-81b9cf8028a17bdbdaa0da80b735b32150d4e89e.zip | |
bpf: add a test case for helper bpf_perf_prog_read_value
The bpf sample program trace_event is enhanced to use the new
helper to print out enabled/running time.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf/trace_event_kern.c')
| -rw-r--r-- | samples/bpf/trace_event_kern.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/samples/bpf/trace_event_kern.c b/samples/bpf/trace_event_kern.c index 41b6115a32eb..a77a583d94d4 100644 --- a/samples/bpf/trace_event_kern.c +++ b/samples/bpf/trace_event_kern.c @@ -37,10 +37,14 @@ struct bpf_map_def SEC("maps") stackmap = { SEC("perf_event") int bpf_prog1(struct bpf_perf_event_data *ctx) { + char time_fmt1[] = "Time Enabled: %llu, Time Running: %llu"; + char time_fmt2[] = "Get Time Failed, ErrCode: %d"; char fmt[] = "CPU-%d period %lld ip %llx"; u32 cpu = bpf_get_smp_processor_id(); + struct bpf_perf_event_value value_buf; struct key_t key; u64 *val, one = 1; + int ret; if (ctx->sample_period < 10000) /* ignore warmup */ @@ -54,6 +58,12 @@ int bpf_prog1(struct bpf_perf_event_data *ctx) return 0; } + ret = bpf_perf_prog_read_value(ctx, (void *)&value_buf, sizeof(struct bpf_perf_event_value)); + if (!ret) + bpf_trace_printk(time_fmt1, sizeof(time_fmt1), value_buf.enabled, value_buf.running); + else + bpf_trace_printk(time_fmt2, sizeof(time_fmt2), ret); + val = bpf_map_lookup_elem(&counts, &key); if (val) (*val)++; |