The patch titled
Subject: lib/test_bitops: add benchmark test for fns()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
lib-test_bitops-add-benchmark-test-for-fns.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-test_bitops-add-benchmark-test-for-fns.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kuan-Wei Chiu <visitorckw@xxxxxxxxx>
Subject: lib/test_bitops: add benchmark test for fns()
Date: Thu, 2 May 2024 17:24:42 +0800
Patch series "bitops: Optimize fns() for improved performance", v5.
This patch series optimizes the fns() function by avoiding repeated calls
to __ffs(). Additionally, tests for fns() have been added in
lib/test_bitops.c.
This patch (of 2):
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
Link: https://lkml.kernel.org/r/20240502092443.6845-1-visitorckw@xxxxxxxxx
Link: https://lkml.kernel.org/r/20240502092443.6845-2-visitorckw@xxxxxxxxx
Signed-off-by: Kuan-Wei Chiu <visitorckw@xxxxxxxxx>
Suggested-by: Yury Norov <yury.norov@xxxxxxxxx>
Cc: Ching-Chun (Jim) Huang <jserv@xxxxxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_bitops.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
--- a/lib/test_bitops.c~lib-test_bitops-add-benchmark-test-for-fns
+++ a/lib/test_bitops.c
@@ -50,6 +50,26 @@ static unsigned long order_comb_long[][2
};
#endif
+static int __init test_fns(void)
+{
+ static unsigned long buf[10000] __initdata;
+ static volatile __used unsigned long tmp __initdata;
+ unsigned int i, n;
+ ktime_t time;
+
+ get_random_bytes(buf, sizeof(buf));
+ 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 +114,8 @@ static int __init test_bitops_startup(vo
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;
_
Patches currently in -mm which might be from visitorckw@xxxxxxxxx are
lib-test_bitops-add-benchmark-test-for-fns.patch
bitops-optimize-fns-for-improved-performance.patch
