perf, bpf: Introduce PERF_RECORD_BPF_EVENT

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>

1 files changed, 28 insertions, 1 deletions

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 1dee5c8f166b..7198ddd0c6b1 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -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