From: Eelco Chaudron <echaudro@redhat.com>
Date: Tue, 26 May 2020 11:21:42 +0200
Subject: libbpf: Add API to consume the perf ring buffer content
Patch-mainline: v5.8-rc1
Git-commit: 272d51af32890632134845ddf35318c11da20c7b
References: bsc#1177028
This new API, perf_buffer__consume, can be used as follows:
- When you have a perf ring where wakeup_events is higher than 1,
and you have remaining data in the rings you would like to pull
out on exit (or maybe based on a timeout).
- For low latency cases where you burn a CPU that constantly polls
the queues.
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/159048487929.89441.7465713173442594608.stgit@ebuild
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Gary Lin <glin@suse.com>
---
tools/lib/bpf/libbpf.c | 19 +++++++++++++++++++
tools/lib/bpf/libbpf.h | 1 +
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 21 insertions(+)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8459,6 +8459,25 @@ int perf_buffer__poll(struct perf_buffer
return cnt < 0 ? -errno : cnt;
}
+int perf_buffer__consume(struct perf_buffer *pb)
+{
+ int i, err;
+
+ for (i = 0; i < pb->cpu_cnt; i++) {
+ struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
+
+ if (!cpu_buf)
+ continue;
+
+ err = perf_buffer__process_records(pb, cpu_buf);
+ if (err) {
+ pr_warning("error while processing records: %d\n", err);
+ return err;
+ }
+ }
+ return 0;
+}
+
struct bpf_prog_info_array_desc {
int array_offset; /* e.g. offset of jited_prog_insns */
int count_offset; /* e.g. offset of jited_prog_len */
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -533,6 +533,7 @@ perf_buffer__new_raw(int map_fd, size_t
LIBBPF_API void perf_buffer__free(struct perf_buffer *pb);
LIBBPF_API int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms);
+LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb);
typedef enum bpf_perf_event_ret
(*bpf_perf_event_print_t)(struct perf_event_header *hdr,
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -262,4 +262,5 @@ LIBBPF_0.0.9 {
bpf_link_get_fd_by_id;
bpf_link_get_next_id;
bpf_program__attach_iter;
+ perf_buffer__consume;
} LIBBPF_0.0.8;