Re: [PATCH bpf-next 4/4] selftests/bpf: Allow to benchmark trigger with stacktrace

On Thu, Jan 15, 2026 at 10:50:13AM -0800, Andrii Nakryiko wrote:

SNIP

quoted

quoted

diff --git a/tools/testing/selftests/bpf/benchs/bench_trigger.c b/tools/testing/selftests/bpf/benchs/bench_trigger.c
index 34018fc3927f..aeec9edd3851 100644
--- a/tools/testing/selftests/bpf/benchs/bench_trigger.c
+++ b/tools/testing/selftests/bpf/benchs/bench_trigger.c

@@ -146,6 +146,7 @@ static void setup_ctx(void)
        bpf_program__set_autoload(ctx.skel->progs.trigger_driver, true);

        ctx.skel->rodata->batch_iters = args.batch_iters;
+       ctx.skel->rodata->stacktrace = env.stacktrace;
 }

 static void load_ctx(void)

diff --git a/tools/testing/selftests/bpf/progs/trigger_bench.c b/tools/testing/selftests/bpf/progs/trigger_bench.c
index 2898b3749d07..479400d96fa4 100644
--- a/tools/testing/selftests/bpf/progs/trigger_bench.c
+++ b/tools/testing/selftests/bpf/progs/trigger_bench.c

@@ -25,6 +25,23 @@ static __always_inline void inc_counter(void)
        __sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
 }

+volatile const int stacktrace;
+
+typedef __u64 stack_trace_t[128];
+
+struct {
+       __uint(type, BPF_MAP_TYPE_STACK_TRACE);
+       __uint(max_entries, 16384);
+       __type(key, __u32);
+       __type(value, stack_trace_t);
+} stackmap SEC(".maps");

oh, and why bother with STACK_TRACE map, just call bpf_get_stack() API
and have maybe per-CPU scratch array for stack trace (per-CPU so that
in multi-cpu benchmarks they don't just contend on the same cache
lines)

ok, will change

thanks,
jirka