#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/timex.h>
#include <linux/stacktrace.h>

#define MAX_LOOP 1000
#define MAX_CALL 10
#define MAX_STACK 32

unsigned long stack_entries[MAX_STACK];

void stackdump(void)
{
	struct stack_trace st;
	st.max_entries = MAX_STACK;
	st.entries = stack_entries;

	save_stack_trace(&st);
}

void alpha(unsigned long call)
{
	if (call)
		alpha(--call);
	else
		stackdump();
}

static void bench_loop(void)
{
	u64 st, ed;
	unsigned long count;
	unsigned long flags;

	pr_info("Start benchmarking.\n");
	local_irq_save(flags);
	st = get_cycles();
	for (count = 0; count < MAX_LOOP; count++)
		alpha(MAX_CALL);
	ed = get_cycles();
	local_irq_restore(flags);
	pr_info("End benchmarking. Elapsed: %lu cycles, loop count:%lu\n",
		(unsigned long)(ed - st), count);
}

static int __init bench_init(void)
{
	bench_loop();
	return 0;
}

static void __exit bench_exit(void)
{
}

module_init(bench_init)
module_exit(bench_exit)
MODULE_LICENSE("GPL");