sample_cb
perf_buffer_sample_fn sample_cb,
p.sample_cb = sample_cb;
pb->sample_cb = p->sample_cb;
if (pb->sample_cb)
pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx,
ring_buffer_sample_fn sample_cb, void *ctx);
perf_buffer_sample_fn sample_cb, perf_buffer_lost_fn lost_cb, void *ctx,
r->sample_cb = sample_cb;
ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx,
err = ring_buffer__add(rb, map_fd, sample_cb, ctx);
ring_buffer_sample_fn sample_cb;
err = r->sample_cb(r->ctx, sample, len);
ring_buffer_sample_fn sample_cb, void *ctx)
perf_buffer_sample_fn sample_cb;