[PATCH 1/2] selftests: vm: add KSM merging time test

Zhansaya Bagdauletkyzy
2021-08-01T15:44:37Z

Add ksm_merge_time() function to determine speed and time needed for
merging. The total spent time is shown in seconds while speed is
in MB/s. User must specify the size of duplicated memory area (in MB)
before running the test.

The test is run as follows: ./ksm_tests -P -s 100
The output:
Total size: 100 MB
Total time: 0.309561 s
Average speed: 323 MB/s

Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
---
tools/testing/selftests/vm/ksm_tests.c | 76 ++++++++++++++++++++++++--
1 file changed, 72 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c
index cdeb4a028538..91c6ff496655 100644
--- a/tools/testing/selftests/vm/ksm_tests.c
+++ b/tools/testing/selftests/vm/ksm_tests.c
@@ -7,6 +7,7 @@
#include <numa.h>

#include "../kselftest.h"
+#include "../../../../include/vdso/time64.h"

#define KSM_SYSFS_PATH "/sys/kernel/mm/ksm/"
#define KSM_FP(s) (KSM_SYSFS_PATH s)
@@ -15,6 +16,7 @@
#define KSM_PROT_STR_DEFAULT "rw"
#define KSM_USE_ZERO_PAGES_DEFAULT false
#define KSM_MERGE_ACROSS_NODES_DEFAULT true
+#define MB_TO_B 1000000ul

struct ksm_sysfs {
unsigned long max_page_sharing;
@@ -30,7 +32,8 @@ enum ksm_test_name {
CHECK_KSM_MERGE,
CHECK_KSM_UNMERGE,
CHECK_KSM_ZERO_PAGE_MERGE,
- CHECK_KSM_NUMA_MERGE
+ CHECK_KSM_NUMA_MERGE,
+ KSM_MERGE_TIME
};

static int ksm_write_sysfs(const char *file_path, unsigned long val)
@@ -86,13 +89,16 @@ static int str_to_prot(char *prot_str)
static void print_help(void)
{
printf("usage: ksm_tests [-h] <test type> [-a prot] [-p page_count] [-l timeout]\n"
- "[-z use_zero_pages] [-m merge_across_nodes]\n");
+ "[-z use_zero_pages] [-m merge_across_nodes] [-s size]\n");

printf("Supported <test type>:\n"
" -M (page merging)\n"
" -Z (zero pages merging)\n"
" -N (merging of pages in different NUMA nodes)\n"
- " -U (page unmerging)\n\n");
+ " -U (page unmerging)\n"
+ " -P evaluate merging time and speed.\n"
+ " For this test, the size of duplicated memory area (in MB)\n"
+ " must be provided using -s option\n\n");

printf(" -a: specify the access protections of pages.\n"
" <prot> must be of the form [rwx].\n"
@@ -105,6 +111,7 @@ static void print_help(void)
" Default: %d\n", KSM_USE_ZERO_PAGES_DEFAULT);
printf(" -m: change merge_across_nodes tunable\n"
" Default: %d\n", KSM_MERGE_ACROSS_NODES_DEFAULT);
+ printf(" -s: the size of duplicated memory area (in MB)\n");

exit(0);
}
@@ -407,6 +414,49 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
return KSFT_FAIL;
}

+static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size)
+{
+ void *map_ptr;
+ struct timespec start_time, end_time;
+ long scan_time_s, scan_time_ns;
+ int avg_speed;
+
+ map_size *= MB_TO_B;
+
+ map_ptr = allocate_memory(NULL, prot, mapping, '*', map_size);
+ if (!map_ptr)
+ return KSFT_FAIL;
+
+ if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
+ perror("clock_gettime");
+ goto err_out;
+ }
+ if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
+ goto err_out;
+ if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
+ perror("clock_gettime");
+ goto err_out;
+ }
+
+ scan_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC +
+ (end_time.tv_nsec - start_time.tv_nsec);
+ scan_time_s = scan_time_ns / NSEC_PER_SEC;
+ scan_time_ns %= NSEC_PER_SEC;
+ avg_speed = map_size / (scan_time_s * USEC_PER_SEC + scan_time_ns / NSEC_PER_USEC);
+
+ printf("Total size: %lu MB\n", map_size / MB_TO_B);
+ printf("Total time: %ld.%06ld s\n", scan_time_s, scan_time_ns / NSEC_PER_USEC);
+ printf("Average speed: %d MB/s\n", avg_speed);
+
+ munmap(map_ptr, map_size);
+ return KSFT_PASS;
+
+err_out:
+ printf("Not OK\n");
+ munmap(map_ptr, map_size);
+ return KSFT_FAIL;
+}
+
int main(int argc, char *argv[])
{
int ret, opt;
@@ -418,8 +468,9 @@ int main(int argc, char *argv[])
int test_name = CHECK_KSM_MERGE;
bool use_zero_pages = KSM_USE_ZERO_PAGES_DEFAULT;
bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT;
+ long size_MB = 0;

- while ((opt = getopt(argc, argv, "ha:p:l:z:m:MUZN")) != -1) {
+ while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNP")) != -1) {
switch (opt) {
case 'a':
prot = str_to_prot(optarg);
@@ -453,6 +504,12 @@ int main(int argc, char *argv[])
else
merge_across_nodes = 1;
break;
+ case 's':
+ size_MB = atoi(optarg);
+ if (size_MB <= 0) {
+ printf("Size must be greater than 0\n");
+ return KSFT_FAIL;
+ }
case 'M':
break;
case 'U':
@@ -464,6 +521,9 @@ int main(int argc, char *argv[])
case 'N':
test_name = CHECK_KSM_NUMA_MERGE;
break;
+ case 'P':
+ test_name = KSM_MERGE_TIME;
+ break;
default:
return KSFT_FAIL;
}
@@ -505,6 +565,14 @@ int main(int argc, char *argv[])
ret = check_ksm_numa_merge(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
merge_across_nodes, page_size);
break;
+ case KSM_MERGE_TIME:
+ if (size_MB == 0) {
+ printf("Option '-s' is required.\n");
+ return KSFT_FAIL;
+ }
+ ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
+ size_MB);
+ break;
}

if (ksm_restore(&ksm_sysfs_old)) {
--
2.25.1