On Mon, Sep 08, 2025 at 07:36:22PM +0800, Tao Chen wrote:
> ...
> test_stacktrace_map:PASS:compare_stack_ips stackmap vs. stack_amap 0 nsec
> test_stacktrace_map:PASS:stack_key_map lookup 0 nsec
> test_stacktrace_map:PASS:stackmap lookup and detele 0 nsec
> #397 stacktrace_map:OK
> ...
>
> Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/stacktrace_map.c | 18 +++++++++++++++++-
> .../selftests/bpf/progs/test_stacktrace_map.c | 12 +++++++++++-
> 2 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_map.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_map.c
> index 84a7e405e91..496c4dcf4ea 100644
> --- a/tools/testing/selftests/bpf/prog_tests/stacktrace_map.c
> +++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_map.c
> @@ -3,7 +3,7 @@
>
> void test_stacktrace_map(void)
> {
> - int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
> + int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd, stack_key_map_fd;
> const char *prog_name = "oncpu";
> int err, prog_fd, stack_trace_len;
> const char *file = "./test_stacktrace_map.bpf.o";
> @@ -11,6 +11,9 @@ void test_stacktrace_map(void)
> struct bpf_program *prog;
> struct bpf_object *obj;
> struct bpf_link *link;
> + __u32 stackmap_key;
> + char val_buf[PERF_MAX_STACK_DEPTH *
> + sizeof(struct bpf_stack_build_id)];
>
> err = bpf_prog_test_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
> if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
> @@ -41,6 +44,10 @@ void test_stacktrace_map(void)
> if (CHECK_FAIL(stack_amap_fd < 0))
> goto disable_pmu;
>
> + stack_key_map_fd = bpf_find_map(__func__, obj, "stack_key_map");
> + if (CHECK_FAIL(stack_key_map_fd < 0))
> + goto disable_pmu;
> +
> /* give some time for bpf program run */
> sleep(1);
>
> @@ -68,6 +75,15 @@ void test_stacktrace_map(void)
> "err %d errno %d\n", err, errno))
> goto disable_pmu;
>
> + err = bpf_map_lookup_elem(stack_key_map_fd, &key, &stackmap_key);
> + if (CHECK(err, "stack_key_map lookup", "err %d errno %d\n", err, errno))
> + goto disable_pmu;
> +
> + err = bpf_map_lookup_and_delete_elem(stackmap_fd, &stackmap_key, &val_buf);
> + if (CHECK(err, "stackmap lookup and detele",
nit typo 's/detele/delete/'
> + "err %d errno %d\n", err, errno))
> + goto disable_pmu;
should we also check the record got deleted? like make sure following
lookup fails with NOENT:
bpf_map_lookup_elem(stackmap_fd, &stackmap_key, &val_buf)
> +
> disable_pmu:
> bpf_link__destroy(link);
> close_prog:
> diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
> index 47568007b66..d036e8e9c83 100644
> --- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
> +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
> @@ -38,6 +38,13 @@ struct {
> __type(value, stack_trace_t);
> } stack_amap SEC(".maps");
>
> +struct {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u32);
> +} stack_key_map SEC(".maps");
> +
> /* taken from /sys/kernel/tracing/events/sched/sched_switch/format */
> struct sched_switch_args {
> unsigned long long pad;
> @@ -54,7 +61,7 @@ SEC("tracepoint/sched/sched_switch")
> int oncpu(struct sched_switch_args *ctx)
> {
> __u32 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
> - __u32 key = 0, val = 0, *value_p;
> + __u32 key = 0, val = 0, *value_p, stackmap_key = 0;
> void *stack_p;
>
> value_p = bpf_map_lookup_elem(&control_map, &key);
> @@ -64,6 +71,9 @@ int oncpu(struct sched_switch_args *ctx)
> /* The size of stackmap and stackid_hmap should be the same */
> key = bpf_get_stackid(ctx, &stackmap, 0);
> if ((int)key >= 0) {
> + val = key;
> + bpf_map_update_elem(&stack_key_map, &stackmap_key, &val, 0);
why not use '&key' directly as the update value?
jirka
> + val = 0;
> bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
> stack_p = bpf_map_lookup_elem(&stack_amap, &key);
> if (stack_p)
> --
> 2.48.1
>
>
