Commit 0a2c6664 authored by Kuan-Wei Chiu's avatar Kuan-Wei Chiu Committed by Yury Norov
Browse files

lib/test_bitops: Add benchmark test for fns() 



Introduce a benchmark test for the fns(). It measures the total time
taken by fns() to process 10,000 test data generated using
get_random_bytes() for each n in the range [0, BITS_PER_LONG).

example:
test_bitops: fns:             7637268 ns

CC: Andrew Morton <akpm@linux-foundation.org>
CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
CC: David Laight <David.Laight@aculab.com>
Signed-off-by: default avatarKuan-Wei Chiu <visitorckw@gmail.com>
Suggested-by: default avatarYury Norov <yury.norov@gmail.com>
Signed-off-by: default avatarYury Norov <yury.norov@gmail.com>
parent efe3a85e

lib/test_bitops.c

+28 −0
Original line number Diff line number Diff line
@@ -5,9 +5,11 @@ 


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/cleanup.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/printk.h>

#include <linux/slab.h>



/* a tiny module only meant to test

 *
@@ -50,6 +52,30 @@ static unsigned long order_comb_long[][2] = { 
};

#endif



static int __init test_fns(void)

{

	static volatile __always_used unsigned long tmp __initdata;

	unsigned long *buf __free(kfree) = NULL;

	unsigned int i, n;

	ktime_t time;



	buf = kmalloc_array(10000, sizeof(unsigned long), GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	get_random_bytes(buf, 10000 * sizeof(unsigned long));

	time = ktime_get();



	for (n = 0; n < BITS_PER_LONG; n++)

		for (i = 0; i < 10000; i++)

			tmp = fns(buf[i], n);



	time = ktime_get() - time;

	pr_err("fns:  %18llu ns\n", time);



	return 0;

}



static int __init test_bitops_startup(void)

{

	int i, bit_set;
@@ -94,6 +120,8 @@ static int __init test_bitops_startup(void) 
	if (bit_set != BITOPS_LAST)

		pr_err("ERROR: FOUND SET BIT %d\n", bit_set);



	test_fns();



	pr_info("Completed bitops test\n");



	return 0;