path: root/main.c
blob: d538f48c051c435af64ae46993add32d45850998 (plain) (tree)

/* SPDX-License-Identifier: GPL-2.0
 * Copyright (C) 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.

#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
#include "function.h"

static unsigned long stamp = 0;
module_param(stamp, ulong, 0);
int dummy;

static int __init mod_init(void)
	int ret = 0, i;
	cycles_t start, end;
	unsigned long flags;

	spin_lock_irqsave(&lock, flags);
	for (i = 0; i < WARMUP; ++i)
		ret |= function();

	start = get_cycles();
	for (i = 0; i < TRIALS; ++i)
		ret |= function();
	end = get_cycles();

	spin_unlock_irqrestore(&lock, flags);
	pr_err("%lu: %llu cycles per call\n", stamp, (end - start) / TRIALS);

	/* Don't let compiler be too clever. */
	dummy = ret;
	/* We should never actually agree to insert the module. Choosing
	 * -0x1000 here is an amazing hack. It causes the kernel to not
	 * actually load the module, while the standard userspace tools
	 * don't return an error, because it's too big. */
	return -0x1000;

MODULE_DESCRIPTION("kBench9000 Cycle Counter");
MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");