linux/tools/testing/selftests/bpf/progs/bpf_loop_bench.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */

#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"

char _license[] SEC("license") = "GPL";

u32 nr_loops;
long hits;

static int empty_callback(__u32 index, void *data)
{
	return 0;
}

static int outer_loop(__u32 index, void *data)
{
	bpf_loop(nr_loops, empty_callback, NULL, 0);
	__sync_add_and_fetch(&hits, nr_loops);
	return 0;
}

SEC("fentry/" SYS_PREFIX "sys_getpgid")
int benchmark(void *ctx)
{
	bpf_loop(1000, outer_loop, NULL, 0);
	return 0;
}