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selftests/bpf: Fix perf_buffer test on systems w/ offline CPUs

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Fix up perf_buffer.c selftest to take into account offline/missing CPUs.

Fixes: ee5cf82ce04a ("selftests/bpf: test perf buffer API")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191212013621.1691858-1-andriin@fb.com
This commit is contained in:
Andrii Nakryiko 2019-12-11 17:36:20 -08:00 committed by Alexei Starovoitov
parent 783b8f01f5
commit 91cbdf740a
1 changed files with 24 additions and 5 deletions
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29
tools/testing/selftests/bpf/prog_tests/perf_buffer.c
View File

@ -4,6 +4,7 @@
#include <sched.h>
#include <sys/socket.h>
#include <test_progs.h>
#include "libbpf_internal.h"
static void on_sample(void *ctx, int cpu, void *data, __u32 size)
{
@ -19,7 +20,7 @@ static void on_sample(void *ctx, int cpu, void *data, __u32 size)
void test_perf_buffer(void)
{
int err, prog_fd, nr_cpus, i, duration = 0;
int err, prog_fd, on_len, nr_on_cpus = 0, nr_cpus, i, duration = 0;
const char *prog_name = "kprobe/sys_nanosleep";
const char *file = "./test_perf_buffer.o";
struct perf_buffer_opts pb_opts = {};
@ -29,15 +30,27 @@ void test_perf_buffer(void)
struct bpf_object *obj;
struct perf_buffer *pb;
struct bpf_link *link;
bool *online;
nr_cpus = libbpf_num_possible_cpus();
if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
return;
err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
&online, &on_len);
if (CHECK(err, "nr_on_cpus", "err %d\n", err))
return;
for (i = 0; i < on_len; i++)
if (online[i])
nr_on_cpus++;
/* load program */
err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
return;
if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) {
obj = NULL;
goto out_close;
}
prog = bpf_object__find_program_by_title(obj, prog_name);
if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
@ -64,6 +77,11 @@ void test_perf_buffer(void)
/* trigger kprobe on every CPU */
CPU_ZERO(&cpu_seen);
for (i = 0; i < nr_cpus; i++) {
if (i >= on_len || !online[i]) {
printf("skipping offline CPU #%d\n", i);
continue;
}
CPU_ZERO(&cpu_set);
CPU_SET(i, &cpu_set);
@ -81,8 +99,8 @@ void test_perf_buffer(void)
if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
goto out_free_pb;
if (CHECK(CPU_COUNT(&cpu_seen) != nr_cpus, "seen_cpu_cnt",
"expect %d, seen %d\n", nr_cpus, CPU_COUNT(&cpu_seen)))
if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
"expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
goto out_free_pb;
out_free_pb:
@ -91,4 +109,5 @@ out_detach:
bpf_link__destroy(link);
out_close:
bpf_object__close(obj);
free(online);
}