[PATCH v4 1/2] lib/test_bitops: Add benchmark test for fns()

Kuan-Wei Chiu
2024-05-01T13:20:57Z

Introduce a benchmark test for the fns(). It measures the total time
taken by fns() to process 1,000,000 test data generated using
get_random_bytes() for each n in the range [0, BITS_PER_LONG).

example:
test_bitops: fns: 5876762553 ns, 64000000 iterations

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---

Changes in v4:
- Correct get_random_long() -> get_random_bytes() in the commit
message.

lib/test_bitops.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/lib/test_bitops.c b/lib/test_bitops.c
index 3b7bcbee84db..ed939f124417 100644
--- a/lib/test_bitops.c
+++ b/lib/test_bitops.c
@@ -50,6 +50,26 @@ static unsigned long order_comb_long[][2] = {
};
#endif

+static unsigned long buf[1000000];
+
+static int __init test_fns(void)
+{
+ 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 < 1000000; i++)
+ fns(buf[i], n);
+
+ time = ktime_get() - time;
+ pr_err("fns: %18llu ns, %6d iterations\n", time, BITS_PER_LONG * 1000000);
+
+ return 0;
+}
+
static int __init test_bitops_startup(void)
{
int i, bit_set;
@@ -94,6 +114,8 @@ 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;
--
2.34.1