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authorArnd Bergmann <arnd@arndb.de>2016-08-02 14:04:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-08-02 19:35:08 -0400
commita9bfd3321713ecec86282dd2bec04212189f91f1 (patch)
tree1c5981e2d274c3d3fb3b340724939fffb7747eb8 /lib
parentf003a1f182bb821f13775338a4bf8711830f927a (diff)
downloadlwn-a9bfd3321713ecec86282dd2bec04212189f91f1.tar.gz
lwn-a9bfd3321713ecec86282dd2bec04212189f91f1.zip
crc32: use ktime_get_ns() for measurement
The crc32 test function measures the elapsed time in nanoseconds, but uses 'struct timespec' for that. We want to remove timespec from the kernel for y2038 compatibility, and ktime_get_ns() also helps make the code simpler here. It is also slightly better to use monontonic time, as we are only interested in the time difference. Link: http://lkml.kernel.org/r/20160617143932.3289626-1-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: "David S . Miller" <davem@davemloft.net> 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/crc32.c16
1 files changed, 4 insertions, 12 deletions
diff --git a/lib/crc32.c b/lib/crc32.c
index 9a907d489d95..7fbd1a112b9d 100644
--- a/lib/crc32.c
+++ b/lib/crc32.c
@@ -979,7 +979,6 @@ static int __init crc32c_test(void)
int i;
int errors = 0;
int bytes = 0;
- struct timespec start, stop;
u64 nsec;
unsigned long flags;
@@ -999,20 +998,17 @@ static int __init crc32c_test(void)
local_irq_save(flags);
local_irq_disable();
- getnstimeofday(&start);
+ nsec = ktime_get_ns();
for (i = 0; i < 100; i++) {
if (test[i].crc32c_le != __crc32c_le(test[i].crc, test_buf +
test[i].start, test[i].length))
errors++;
}
- getnstimeofday(&stop);
+ nsec = ktime_get_ns() - nsec;
local_irq_restore(flags);
local_irq_enable();
- nsec = stop.tv_nsec - start.tv_nsec +
- 1000000000 * (stop.tv_sec - start.tv_sec);
-
pr_info("crc32c: CRC_LE_BITS = %d\n", CRC_LE_BITS);
if (errors)
@@ -1065,7 +1061,6 @@ static int __init crc32_test(void)
int i;
int errors = 0;
int bytes = 0;
- struct timespec start, stop;
u64 nsec;
unsigned long flags;
@@ -1088,7 +1083,7 @@ static int __init crc32_test(void)
local_irq_save(flags);
local_irq_disable();
- getnstimeofday(&start);
+ nsec = ktime_get_ns();
for (i = 0; i < 100; i++) {
if (test[i].crc_le != crc32_le(test[i].crc, test_buf +
test[i].start, test[i].length))
@@ -1098,14 +1093,11 @@ static int __init crc32_test(void)
test[i].start, test[i].length))
errors++;
}
- getnstimeofday(&stop);
+ nsec = ktime_get_ns() - nsec;
local_irq_restore(flags);
local_irq_enable();
- nsec = stop.tv_nsec - start.tv_nsec +
- 1000000000 * (stop.tv_sec - start.tv_sec);
-
pr_info("crc32: CRC_LE_BITS = %d, CRC_BE BITS = %d\n",
CRC_LE_BITS, CRC_BE_BITS);