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perf, bpf: Introduce PERF_RECORD_BPF_EVENT

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For better performance analysis of BPF programs, this patch introduces
PERF_RECORD_BPF_EVENT, a new perf_event_type that exposes BPF program
load/unload information to user space.

Each BPF program may contain up to BPF_MAX_SUBPROGS (256) sub programs.
The following example shows kernel symbols for a BPF program with 7 sub
programs:

    ffffffffa0257cf9 t bpf_prog_b07ccb89267cf242_F
    ffffffffa02592e1 t bpf_prog_2dcecc18072623fc_F
    ffffffffa025b0e9 t bpf_prog_bb7a405ebaec5d5c_F
    ffffffffa025dd2c t bpf_prog_a7540d4a39ec1fc7_F
    ffffffffa025fcca t bpf_prog_05762d4ade0e3737_F
    ffffffffa026108f t bpf_prog_db4bd11e35df90d4_F
    ffffffffa0263f00 t bpf_prog_89d64e4abf0f0126_F
    ffffffffa0257cf9 t bpf_prog_ae31629322c4b018__dummy_tracepoi

When a bpf program is loaded, PERF_RECORD_KSYMBOL is generated for each
of these sub programs. Therefore, PERF_RECORD_BPF_EVENT is not needed
for simple profiling.

For annotation, user space need to listen to PERF_RECORD_BPF_EVENT and
gather more information about these (sub) programs via sys_bpf.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradeaed.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-4-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Song Liu 2019-01-17 08:15:15 -08:00 • committed by Arnaldo Carvalho de Melo
parent d764ac6464
commit 6ee52e2a3f
6 changed files with 159 additions and 2 deletions
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29
include/uapi/linux/perf_event.h
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@ -373,7 +373,8 @@ struct perf_event_attr {
write_backward : 1, /* Write ring buffer from end to beginning */
namespaces : 1, /* include namespaces data */
ksymbol : 1, /* include ksymbol events */
__reserved_1 : 34;
bpf_event : 1, /* include bpf events */
__reserved_1 : 33;
union {
__u32 wakeup_events; /* wakeup every n events */
@ -979,6 +980,25 @@ enum perf_event_type {
*/
PERF_RECORD_KSYMBOL = 17,
/*
* Record bpf events:
* enum perf_bpf_event_type {
* PERF_BPF_EVENT_UNKNOWN = 0,
* PERF_BPF_EVENT_PROG_LOAD = 1,
* PERF_BPF_EVENT_PROG_UNLOAD = 2,
* };
*
* struct {
* struct perf_event_header header;
* u16 type;
* u16 flags;
* u32 id;
* u8 tag[BPF_TAG_SIZE];
* struct sample_id sample_id;
* };
*/
PERF_RECORD_BPF_EVENT = 18,
PERF_RECORD_MAX, /* non-ABI */
};
@ -990,6 +1010,13 @@ enum perf_record_ksymbol_type {
#define PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER (1 << 0)
enum perf_bpf_event_type {
PERF_BPF_EVENT_UNKNOWN = 0,
PERF_BPF_EVENT_PROG_LOAD = 1,
PERF_BPF_EVENT_PROG_UNLOAD = 2,
PERF_BPF_EVENT_MAX, /* non-ABI */
};
#define PERF_MAX_STACK_DEPTH 127
#define PERF_MAX_CONTEXTS_PER_STACK 8