Commit de6d014a authored by Song Liu's avatar Song Liu Committed by Daniel Borkmann
Browse files

selftests/bpf: Use read_perf_max_sample_freq() in perf_event_stackmap 



Currently, perf_event sample period in perf_event_stackmap is set too low
that the test fails randomly. Fix this by using the max sample frequency,
from read_perf_max_sample_freq().

Move read_perf_max_sample_freq() to testing_helpers.c. Replace the CHECK()
with if-printf, as CHECK is not available in testing_helpers.c.

Fixes: 1da4864c ("selftests/bpf: Add callchain_stackid")
Signed-off-by: default avatarSong Liu <song@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230412210423.900851-2-song@kernel.org
parent 5a674611

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

+2 −1
Original line number Diff line number Diff line
@@ -63,7 +63,8 @@ void test_perf_event_stackmap(void) 
			PERF_SAMPLE_BRANCH_NO_FLAGS |

			PERF_SAMPLE_BRANCH_NO_CYCLES |

			PERF_SAMPLE_BRANCH_CALL_STACK,

		.sample_period = 5000,

		.freq = 1,

		.sample_freq = read_perf_max_sample_freq(),

		.size = sizeof(struct perf_event_attr),

	};

	struct perf_event_stackmap *skel;

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

+0 −15
Original line number Diff line number Diff line
@@ -2,21 +2,6 @@ 
#include <test_progs.h>

#include "test_stacktrace_build_id.skel.h"



static __u64 read_perf_max_sample_freq(void)

{

	__u64 sample_freq = 5000; /* fallback to 5000 on error */

	FILE *f;

	__u32 duration = 0;



	f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");

	if (f == NULL)

		return sample_freq;

	CHECK(fscanf(f, "%llu", &sample_freq) != 1, "Get max sample rate",

		  "return default value: 5000,err %d\n", -errno);

	fclose(f);

	return sample_freq;

}



void test_stacktrace_build_id_nmi(void)

{

	int control_map_fd, stackid_hmap_fd, stackmap_fd;

tools/testing/selftests/bpf/testing_helpers.c

+20 −0
Original line number Diff line number Diff line
@@ -229,3 +229,23 @@ int bpf_test_load_program(enum bpf_prog_type type, const struct bpf_insn *insns, 


	return bpf_prog_load(type, NULL, license, insns, insns_cnt, &opts);

}



__u64 read_perf_max_sample_freq(void)

{

	__u64 sample_freq = 5000; /* fallback to 5000 on error */

	FILE *f;



	f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");

	if (f == NULL) {

		printf("Failed to open /proc/sys/kernel/perf_event_max_sample_rate: err %d\n"

		       "return default value: 5000\n", -errno);

		return sample_freq;

	}

	if (fscanf(f, "%llu", &sample_freq) != 1) {

		printf("Failed to parse /proc/sys/kernel/perf_event_max_sample_rate: err %d\n"

		       "return default value: 5000\n", -errno);

	}



	fclose(f);

	return sample_freq;

}

tools/testing/selftests/bpf/testing_helpers.h

+2 −0
Original line number Diff line number Diff line
@@ -20,3 +20,5 @@ struct test_filter_set; 
int parse_test_list(const char *s,

		    struct test_filter_set *test_set,

		    bool is_glob_pattern);



__u64 read_perf_max_sample_freq(void);