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benchtests: Fix walking sizes and directions for *-walk benchmarks

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Make the walking benchmarks walk only backwards since copying both
ways is biased in favour of implementations that use non-temporal
stores for larger sizes; falkor is one of them.  This also fixes up
bugs in computation of the result which ended up multiplying the
length with the timing result unnecessarily.

	* benchtests/bench-memcpy-walk.c (do_one_test): Copy only
	backwards.  Fix timing computation.
	* benchtests/bench-memmove-walk.c (do_one_test): Likewise.
	* benchtests/bench-memset-walk.c (do_one_test): Walk backwards
	on memset by N at a time.  Fix timing computation.
This commit is contained in:
Siddhesh Poyarekar 2017-11-20 17:55:59 +05:30
parent a465b89ee8
commit 4d7632ff68
4 changed files with 20 additions and 21 deletions
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8
ChangeLog
View file

@ -1,3 +1,11 @@
2017-11-20 Siddhesh Poyarekar <siddhesh@sourceware.org>
* benchtests/bench-memcpy-walk.c (do_one_test): Copy only
backwards. Fix timing computation.
* benchtests/bench-memmove-walk.c (do_one_test): Likewise.
* benchtests/bench-memset-walk.c (do_one_test): Walk backwards
on memset by N at a time. Fix timing computation.
2017-11-20 Florian Weimer <fweimer@redhat.com>
* manual/llio.texi (Memory-mapped I/O): Document MAP_HUGETLB,

14
benchtests/bench-memcpy-walk.c
View file

@ -47,26 +47,22 @@ static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl, char *dst, char *src,
size_t len)
{
size_t i, iters = MIN_PAGE_SIZE / len;
size_t i = 0;
timing_t start, stop, cur;
char *dst_end = dst + MIN_PAGE_SIZE - len;
char *src_end = src + MIN_PAGE_SIZE - len;
TIMING_NOW (start);
/* Copy the entire buffer back and forth, LEN at a time. */
for (i = 0; i < iters && dst_end >= dst && src <= src_end; src++, dst_end--)
{
CALL (impl, dst_end, src, len);
CALL (impl, src, dst_end, len);
i += 2;
}
/* Copy the entire buffer backwards, LEN at a time. */
for (; src_end >= src && dst_end >= dst; src_end -= len, dst_end -= len, i++)
CALL (impl, src_end, dst_end, len);
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
/* Get time taken per function call. */
json_element_double (json_ctx, (double) cur * len / i);
json_element_double (json_ctx, (double) cur / i);
}
static void

15
benchtests/bench-memmove-walk.c
View file

@ -47,26 +47,22 @@ static void
do_one_test (json_ctx_t *json_ctx, impl_t *impl, char *dst, char *src,
size_t len)
{
size_t i, iters = MIN_PAGE_SIZE / len;
size_t i = 0;
timing_t start, stop, cur;
char *dst_end = dst + MIN_PAGE_SIZE - len;
char *src_end = src + MIN_PAGE_SIZE - len;
TIMING_NOW (start);
/* Copy the entire buffer back and forth, LEN at a time. */
for (i = 0; i < iters && dst_end >= dst && src <= src_end; src++, dst_end--)
{
CALL (impl, dst_end, src, len);
CALL (impl, src, dst_end, len);
i += 2;
}
/* Copy the entire buffer backwards, LEN at a time. */
for (; src_end >= src && dst <= dst_end; dst += len, src_end -= len, i++)
CALL (impl, dst, src_end, len);
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
/* Get time taken per function call. */
json_element_double (json_ctx, (double) cur * len / i);
json_element_double (json_ctx, (double) cur / i);
}
static void
@ -79,7 +75,6 @@ do_test (json_ctx_t *json_ctx, size_t len, bool overlap)
if (overlap)
buf2 = buf1;
/* First the non-overlapping moves. */
FOR_EACH_IMPL (impl, 0)
do_one_test (json_ctx, impl, (char *) buf2, (char *) buf1, len);

4
benchtests/bench-memset-walk.c
View file

@ -66,14 +66,14 @@ do_one_test (json_ctx_t *json_ctx, impl_t *impl, CHAR *s, CHAR *s_end,
timing_t start, stop, cur;
TIMING_NOW (start);
for (i = 0; i < iters && s <= s_end; s++, i++)
for (i = 0; i < iters && s <= s_end; s_end -= n, i++)
CALL (impl, s, c, n);
TIMING_NOW (stop);
TIMING_DIFF (cur, start, stop);
/* Get time taken per function call. */
json_element_double (json_ctx, (double) cur * n / i);
json_element_double (json_ctx, (double) cur / i);
}
static void