The patch titled
Subject: lib/find_bit_benchmark.c: improvements
has been added to the -mm tree. Its filename is
lib-find_bit_benchmarkc-improvements.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-find_bit_benchmarkc-improvements.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-find_bit_benchmarkc-improvements.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxx>
Tested-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Clement Courbet <courbet@xxxxxxxxxx>
Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/find_bit_benchmark.c | 47 ++++++++++++++++---------------------
1 file changed, 21 insertions(+), 26 deletions(-)
diff -puN lib/find_bit_benchmark.c~lib-find_bit_benchmarkc-improvements lib/find_bit_benchmark.c
--- a/lib/find_bit_benchmark.c~lib-find_bit_benchmarkc-improvements
+++ a/lib/find_bit_benchmark.c
@@ -43,16 +43,15 @@ static DECLARE_BITMAP(bitmap, BITMAP_LEN
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(vo
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(con
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_bi
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(con
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");
_
Patches currently in -mm which might be from ynorov@xxxxxxxxxxxxxxxxxx are
lib-test_find_bitc-rename-to-find_bit_benchmarkc.patch
lib-find_bit_benchmarkc-improvements.patch
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