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authorYury Norov <ynorov@caviumnetworks.com>2018-02-06 15:38:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:44 -0800
commit15ff67bf85c6c02ab7d850deea0199516e8f16a0 (patch)
tree69383df4c252a1e4dd6ce7a58ba30b891e348e43 /lib
parentdceeb3e7fd5cdafb6b8f70321fc4d994c95c3554 (diff)
downloadlinux-15ff67bf85c6c02ab7d850deea0199516e8f16a0.tar.bz2
lib/find_bit_benchmark.c: improvements
As suggested in review comments: * printk: align numbers using whitespaces instead of tabs; * return error value from init() to avoid calling rmmod if testing again; * use ktime_get instead of get_cycles as some arches don't support it; The output in dmesg (on QEMU arm64): [ 38.823430] Start testing find_bit() with random-filled bitmap [ 38.845358] find_next_bit: 20138448 ns, 163968 iterations [ 38.856217] find_next_zero_bit: 10615328 ns, 163713 iterations [ 38.863564] find_last_bit: 7111888 ns, 163967 iterations [ 40.944796] find_first_bit: 2081007216 ns, 163968 iterations [ 40.944975] [ 40.944975] Start testing find_bit() with sparse bitmap [ 40.945268] find_next_bit: 73216 ns, 656 iterations [ 40.967858] find_next_zero_bit: 22461008 ns, 327025 iterations [ 40.968047] find_last_bit: 62320 ns, 656 iterations [ 40.978060] find_first_bit: 9889360 ns, 656 iterations Link: http://lkml.kernel.org/r/20171124143040.a44jvhmnaiyedg2i@yury-thinkpad Signed-off-by: Yury Norov <ynorov@caviumnetworks.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Clement Courbet <courbet@google.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/find_bit_benchmark.c47
1 files changed, 21 insertions, 26 deletions
diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
index f4394a36f9aa..67b19233c28f 100644
--- a/lib/find_bit_benchmark.c
+++ b/lib/find_bit_benchmark.c
@@ -43,16 +43,15 @@ static DECLARE_BITMAP(bitmap, BITMAP_LEN) __initdata;
static int __init test_find_first_bit(void *bitmap, unsigned long len)
{
unsigned long i, cnt;
- cycles_t cycles;
+ ktime_t time;
- cycles = get_cycles();
+ time = ktime_get();
for (cnt = i = 0; i < len; cnt++) {
i = find_first_bit(bitmap, len);
__clear_bit(i, bitmap);
}
- cycles = get_cycles() - cycles;
- pr_err("find_first_bit:\t\t%llu cycles,\t%ld iterations\n",
- (u64)cycles, cnt);
+ time = ktime_get() - time;
+ pr_err("find_first_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -60,14 +59,13 @@ static int __init test_find_first_bit(void *bitmap, unsigned long len)
static int __init test_find_next_bit(const void *bitmap, unsigned long len)
{
unsigned long i, cnt;
- cycles_t cycles;
+ ktime_t time;
- cycles = get_cycles();
+ time = ktime_get();
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_bit(bitmap, BITMAP_LEN, i) + 1;
- cycles = get_cycles() - cycles;
- pr_err("find_next_bit:\t\t%llu cycles,\t%ld iterations\n",
- (u64)cycles, cnt);
+ time = ktime_get() - time;
+ pr_err("find_next_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -75,14 +73,13 @@ static int __init test_find_next_bit(const void *bitmap, unsigned long len)
static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
{
unsigned long i, cnt;
- cycles_t cycles;
+ ktime_t time;
- cycles = get_cycles();
+ time = ktime_get();
for (cnt = i = 0; i < BITMAP_LEN; cnt++)
i = find_next_zero_bit(bitmap, len, i) + 1;
- cycles = get_cycles() - cycles;
- pr_err("find_next_zero_bit:\t%llu cycles,\t%ld iterations\n",
- (u64)cycles, cnt);
+ time = ktime_get() - time;
+ pr_err("find_next_zero_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -90,9 +87,9 @@ static int __init test_find_next_zero_bit(const void *bitmap, unsigned long len)
static int __init test_find_last_bit(const void *bitmap, unsigned long len)
{
unsigned long l, cnt = 0;
- cycles_t cycles;
+ ktime_t time;
- cycles = get_cycles();
+ time = ktime_get();
do {
cnt++;
l = find_last_bit(bitmap, len);
@@ -100,9 +97,8 @@ static int __init test_find_last_bit(const void *bitmap, unsigned long len)
break;
len = l;
} while (len);
- cycles = get_cycles() - cycles;
- pr_err("find_last_bit:\t\t%llu cycles,\t%ld iterations\n",
- (u64)cycles, cnt);
+ time = ktime_get() - time;
+ pr_err("find_last_bit: %18llu ns, %6ld iterations\n", time, cnt);
return 0;
}
@@ -132,13 +128,12 @@ static int __init find_bit_test(void)
test_find_last_bit(bitmap, BITMAP_LEN);
test_find_first_bit(bitmap, BITMAP_LEN);
- return 0;
+ /*
+ * Everything is OK. Return error just to let user run benchmark
+ * again without annoying rmmod.
+ */
+ return -EINVAL;
}
module_init(find_bit_test);
-static void __exit test_find_bit_cleanup(void)
-{
-}
-module_exit(test_find_bit_cleanup);
-
MODULE_LICENSE("GPL");