selftests/bpf: simplify the kernel_count bench trigger

Remove the "trigger_count" in trigger_bench.c and reuse trigger_driver()
instead for trigger_kernel_count_setup().

With the calling to bpf_get_numa_node_id(), the result for "kernel_count"
will become a little more accurate.

It will also easier if we want to test the performance of livepatch, just
hook the bpf_get_numa_node_id() and run the "kernel_count" bench trigger.

Signed-off-by: Menglong Dong <[email protected]>

Author: image-dragon

tools/testing/selftests/bpf/benchs/bench_trigger.c

@@ -179,11 +179,8 @@ static void trigger_syscall_count_setup(void)
 static void trigger_kernel_count_setup(void)
 {
 	setup_ctx();
-	bpf_program__set_autoload(ctx.skel->progs.trigger_driver, false);
-	bpf_program__set_autoload(ctx.skel->progs.trigger_count, true);
+	ctx.skel->rodata->kernel_count = 1;
 	load_ctx();
-	/* override driver program */
-	ctx.driver_prog_fd = bpf_program__fd(ctx.skel->progs.trigger_count);
 }
 
 static void trigger_kprobe_setup(void)

tools/testing/selftests/bpf/progs/trigger_bench.c

@@ -39,26 +39,19 @@ int bench_trigger_uprobe_multi(void *ctx)
 	return 0;
 }
 
+const volatile int kernel_count = 0;
 const volatile int batch_iters = 0;
 
-SEC("?raw_tp")
-int trigger_count(void *ctx)
-{
-	int i;
-
-	for (i = 0; i < batch_iters; i++)
-		inc_counter();
-
-	return 0;
-}
-
 SEC("?raw_tp")
 int trigger_driver(void *ctx)
 {
 	int i;
 
-	for (i = 0; i < batch_iters; i++)
+	for (i = 0; i < batch_iters; i++) {
 		(void)bpf_get_numa_node_id(); /* attach point for benchmarking */
+		if (kernel_count)
+			inc_counter();
+	}
 
 	return 0;
 }