Commit 3ebf5212 authored by Song Liu's avatar Song Liu Committed by Andrii Nakryiko
Browse files

selftests/bpf: Use PERF_COUNT_HW_CPU_CYCLES event for get_branch_snapshot 



perf_event with type=PERF_TYPE_RAW and config=0x1b00 turned out to be not
reliable in ensuring LBR is active. Thus, test_progs:get_branch_snapshot is
not reliable in some systems. Replace it with PERF_COUNT_HW_CPU_CYCLES
event, which gives more consistent results.

Signed-off-by: default avatarSong Liu <song@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230407190130.2093736-1-song@kernel.org
parent f3f21349

tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c

+2 −2
Original line number Diff line number Diff line
@@ -37,8 +37,8 @@ static int create_perf_events(void) 


	/* create perf event */

	attr.size = sizeof(attr);

	attr.type = PERF_TYPE_RAW;

	attr.config = 0x1b00;

	attr.type = PERF_TYPE_HARDWARE;

	attr.config = PERF_COUNT_HW_CPU_CYCLES;

	attr.sample_type = PERF_SAMPLE_BRANCH_STACK;

	attr.branch_sample_type = PERF_SAMPLE_BRANCH_KERNEL |

		PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;