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authorAndrii Nakryiko <andriin@fb.com>2019-07-06 11:06:24 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2019-07-08 15:35:43 +0200
commitfb84b8224655309e7d38f989e426b82a4543f115 (patch)
tree563183fc32d1afc4149e61e7423429d6fd1bd4f7 /tools/lib/bpf/libbpf.map
parentselftests/bpf: add test_tcp_rtt to .gitignore (diff)
downloadlinux-dev-fb84b8224655309e7d38f989e426b82a4543f115.tar.xz
linux-dev-fb84b8224655309e7d38f989e426b82a4543f115.zip
libbpf: add perf buffer API
BPF_MAP_TYPE_PERF_EVENT_ARRAY map is often used to send data from BPF program to user space for additional processing. libbpf already has very low-level API to read single CPU perf buffer, bpf_perf_event_read_simple(), but it's hard to use and requires a lot of code to set everything up. This patch adds perf_buffer abstraction on top of it, abstracting setting up and polling per-CPU logic into simple and convenient API, similar to what BCC provides. perf_buffer__new() sets up per-CPU ring buffers and updates corresponding BPF map entries. It accepts two user-provided callbacks: one for handling raw samples and one for get notifications of lost samples due to buffer overflow. perf_buffer__new_raw() is similar, but provides more control over how perf events are set up (by accepting user-provided perf_event_attr), how they are handled (perf_event_header pointer is passed directly to user-provided callback), and on which CPUs ring buffers are created (it's possible to provide a list of CPUs and corresponding map keys to update). This API allows advanced users fuller control. perf_buffer__poll() is used to fetch ring buffer data across all CPUs, utilizing epoll instance. perf_buffer__free() does corresponding clean up and unsets FDs from BPF map. All APIs are not thread-safe. User should ensure proper locking/coordination if used in multi-threaded set up. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to '')
-rw-r--r--tools/lib/bpf/libbpf.map4
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index e6b7d4edbc93..f9d316e873d8 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -179,4 +179,8 @@ LIBBPF_0.0.4 {
btf_dump__new;
btf__parse_elf;
libbpf_num_possible_cpus;
+ perf_buffer__free;
+ perf_buffer__new;
+ perf_buffer__new_raw;
+ perf_buffer__poll;
} LIBBPF_0.0.3;