On 07/07/2022, Song Liu wrote:
Hi Song Liu, thank you for the fast reply, I'll add comments on top
of your original email.
I will not be available through out next week, so sorry if I'll have a
late reply for follow ups.
Thanks in advance,
-- Jon.
On Thu, Jul 7, 2022 at 12:14 AM Jon Doron <arilou@xxxxxxxxx> wrote:
Please prefix the patch with the target tree (bpf or bpf-next). For example,
this patch should go via bpf-next.
Done
From: Jon Doron <jond@xxxxxx>
Add API for perfbuf to support writing a custom event reader.
This is too brief for such change. It is ok to duplicate text from the cover
letter.
Done
Please also update libbpf.map.
Done
Also, we should add a selftest to use these new APIs.
I'm not sure I'm following here what were you had in mind, in practice I
could just change **bpf_perf_event_read_simple** implementation to use
these new APIs to initialize it's variables (data_head, data_tail,
base, mmap_size) and it would act exactly the same.
Signed-off-by: Jon Doron <jond@xxxxxx>
---
tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 6 ++++++
2 files changed, 46 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e89cc9c885b3..37299aa05185 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -12433,6 +12433,46 @@ static int perf_buffer__process_records(struct perf_buffer *pb,
return 0;
}
+int perf_buffer__raw_ring_buf(const struct perf_buffer *pb, size_t buf_idx,
+ void **base, size_t *buf_size, __u64 *head,
+ __u64 *tail)
Please add comments to each API function.
Done
+{
+ struct perf_cpu_buf *cpu_buf;
+ struct perf_event_mmap_page *header;
+
+ if (buf_idx >= pb->cpu_cnt)
+ return libbpf_err(-EINVAL);
+
+ cpu_buf = pb->cpu_bufs[buf_idx];
+ if (!cpu_buf)
+ return libbpf_err(-ENOENT);
+
+ header = cpu_buf->base;
+ *head = ring_buffer_read_head(header);
+ *tail = header->data_tail;
+ *base = ((__u8 *)header) + pb->page_size;
+ *buf_size = pb->mmap_size;
+ return 0;
+}
+
+int perf_buffer__set_ring_buf_tail(const struct perf_buffer *pb, size_t buf_idx,
+ __u64 tail)
+{
+ struct perf_cpu_buf *cpu_buf;
+ struct perf_event_mmap_page *header;
+
+ if (buf_idx >= pb->cpu_cnt)
+ return libbpf_err(-EINVAL);
+
+ cpu_buf = pb->cpu_bufs[buf_idx];
+ if (!cpu_buf)
+ return libbpf_err(-ENOENT);
+
+ header = cpu_buf->base;
+ ring_buffer_write_tail(header, tail);
+ return 0;
+}
+
int perf_buffer__epoll_fd(const struct perf_buffer *pb)
{
return pb->epoll_fd;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 9e9a3fd3edd8..b6f6b6a12d70 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1381,6 +1381,12 @@ LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb);
LIBBPF_API int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx);
LIBBPF_API size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb);
LIBBPF_API int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx);
+LIBBPF_API int perf_buffer__raw_ring_buf(const struct perf_buffer *pb,
+ size_t buf_idx, void **base,
+ size_t *buf_size, __u64 *head,
+ __u64 *tail);
+LIBBPF_API int perf_buffer__set_ring_buf_tail(const struct perf_buffer *pb,
+ size_t buf_idx, __u64 tail);
typedef enum bpf_perf_event_ret
(*bpf_perf_event_print_t)(struct perf_event_header *hdr,
--
2.36.1
