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crc32: use ktime_get_ns() for measurement

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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>
This commit is contained in:
Arnd Bergmann 2016-08-02 14:04:16 -07:00 committed by Linus Torvalds
parent f003a1f182
commit a9bfd33217
1 changed files with 4 additions and 12 deletions
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16
lib/crc32.c
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@ -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);