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selftests/vm: 8x compaction_test speedup

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This patch reduces the running time for compaction_test from about 27 sec,
to 3.3 sec, which is about an 8x speedup.

These numbers are for an Intel x86_64 system with 32 GB of DRAM.

The compaction_test.c program was spending most of its time doing mmap(),
1 MB at a time, on about 25 GB of memory.

Instead, do the mmaps 100 MB at a time.  (Going past 100 MB doesn't make
things go much faster, because other parts of the program are using the
remaining time.)

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sri Jayaramappa <sjayaram@akamai.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Link: https://lkml.kernel.org/r/20201002080621.551044-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
John Hubbard 2020-10-13 16:57:04 -07:00 committed by Linus Torvalds
parent 74c9da4e1d
commit 1100262037
1 changed files with 6 additions and 5 deletions
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11
tools/testing/selftests/vm/compaction_test.c
View File

@ -18,7 +18,8 @@
#include "../kselftest.h"
#define MAP_SIZE 1048576
#define MAP_SIZE_MB 100
#define MAP_SIZE (MAP_SIZE_MB * 1024 * 1024)
struct map_list {
void *map;
@ -165,7 +166,7 @@ int main(int argc, char **argv)
void *map = NULL;
unsigned long mem_free = 0;
unsigned long hugepage_size = 0;
unsigned long mem_fragmentable = 0;
long mem_fragmentable_MB = 0;
if (prereq() != 0) {
printf("Either the sysctl compact_unevictable_allowed is not\n"
@ -190,9 +191,9 @@ int main(int argc, char **argv)
return -1;
}
mem_fragmentable = mem_free * 0.8 / 1024;
mem_fragmentable_MB = mem_free * 0.8 / 1024;
while (mem_fragmentable > 0) {
while (mem_fragmentable_MB > 0) {
map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0);
if (map == MAP_FAILED)
@ -213,7 +214,7 @@ int main(int argc, char **argv)
for (i = 0; i < MAP_SIZE; i += page_size)
*(unsigned long *)(map + i) = (unsigned long)map + i;
mem_fragmentable--;
mem_fragmentable_MB -= MAP_SIZE_MB;
}
for (entry = list; entry != NULL; entry = entry->next) {