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

On Sun, Aug 1, 2021 at 11:43 AM Zhansaya Bagdauletkyzy zhansayabagdaulet@gmail.com wrote:

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

We should calculate everything in true megabytes.

#define MB (1ul << 20)

Also, print in MiB/s.

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;
  

Should be "unsigned long".

•   int avg_speed;
  

No needed, see below.

•   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);
  

Please remove the above three lines, and replace with bellow suggestions:

•   printf("Total size:    %lu MB\n", map_size / MB_TO_B);
  

printf("Total size: %lu MiB\n", map_size / MB);

•   printf("Total time:    %ld.%06ld s\n", scan_time_s, scan_time_ns / NSEC_PER_USEC);
  

printf("Total time: %ld.%09ld s\n", scan_time_ns / NSEC_PER_SEC, scan_time_ns % NSEC_PER_SEC));

•   printf("Average speed: %d MB/s\n", avg_speed);
  

The following would give a much better precision: printf("Average speed: %.3f MiB/s\n", (map_size / MB) / ((double)scan_time_ns / NSEC_PER_SEC));

•   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