* [PATCH v3 0/2] add KSM performance tests @ 2021-08-19 15:33 Zhansaya Bagdauletkyzy 2021-08-19 15:33 ` [PATCH v3 1/2] selftests: vm: add KSM merging time test Zhansaya Bagdauletkyzy 2021-08-19 15:33 ` [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages Zhansaya Bagdauletkyzy 0 siblings, 2 replies; 7+ messages in thread From: Zhansaya Bagdauletkyzy @ 2021-08-19 15:33 UTC (permalink / raw) To: akpm; +Cc: linux-mm, linux-kselftest, linux-kernel, tyhicks, pasha.tatashin Extend KSM self tests with a performance benchmark. These tests are not part of regular regression testing, as they are mainly intended to be used by developers making changes to the memory management subsystem. This patchset is a respin of the previous series: v2: https://lkml.org/lkml/2021/8/6/422 v1: https://lkml.org/lkml/2021/8/1/130 Zhansaya Bagdauletkyzy (2): selftests: vm: add KSM merging time test selftests: vm: add COW time test for KSM pages v2 -> v3: - address COW test review comments v1 -> v2: - replace MB with MiB - address COW test review comments tools/testing/selftests/vm/ksm_tests.c | 154 ++++++++++++++++++++++++- 1 file changed, 150 insertions(+), 4 deletions(-) -- 2.25.1 ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v3 1/2] selftests: vm: add KSM merging time test 2021-08-19 15:33 [PATCH v3 0/2] add KSM performance tests Zhansaya Bagdauletkyzy @ 2021-08-19 15:33 ` Zhansaya Bagdauletkyzy 2021-08-19 16:29 ` Tyler Hicks 2021-08-19 15:33 ` [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages Zhansaya Bagdauletkyzy 1 sibling, 1 reply; 7+ messages in thread From: Zhansaya Bagdauletkyzy @ 2021-08-19 15:33 UTC (permalink / raw) To: akpm; +Cc: linux-mm, linux-kselftest, linux-kernel, tyhicks, pasha.tatashin 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 MiB/s. User must specify the size of duplicated memory area (in MiB) before running the test. The test is run as follows: ./ksm_tests -P -s 100 The output: Total size: 100 MiB Total time: 0.201106786 s Average speed: 497.248 MiB/s Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com> --- v2 -> v3: - no changes v1 -> v2: As suggested by Pavel, - replace MB with MiB - measure speed more accurately Pavel's comments: https://lkml.org/lkml/2021/8/3/1362 tools/testing/selftests/vm/ksm_tests.c | 74 ++++++++++++++++++++++++-- 1 file changed, 70 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c index cdeb4a028538..432dfe615e50 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 (1ul << 20) 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 MiB)\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 MiB)\n"); exit(0); } @@ -407,6 +414,47 @@ 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; + unsigned long scan_time_ns; + + map_size *= MB; + + 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); + + printf("Total size: %lu MiB\n", map_size / MB); + printf("Total time: %ld.%09ld s\n", scan_time_ns / NSEC_PER_SEC, + scan_time_ns % NSEC_PER_SEC); + 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 +466,9 @@ 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 +502,12 @@ 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 +519,9 @@ 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 +563,14 @@ 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 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v3 1/2] selftests: vm: add KSM merging time test 2021-08-19 15:33 ` [PATCH v3 1/2] selftests: vm: add KSM merging time test Zhansaya Bagdauletkyzy @ 2021-08-19 16:29 ` Tyler Hicks 2021-08-20 17:19 ` Pavel Tatashin 0 siblings, 1 reply; 7+ messages in thread From: Tyler Hicks @ 2021-08-19 16:29 UTC (permalink / raw) To: Zhansaya Bagdauletkyzy Cc: akpm, linux-mm, linux-kselftest, linux-kernel, pasha.tatashin On 2021-08-19 21:33:41, Zhansaya Bagdauletkyzy 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 MiB/s. User must specify the size of duplicated memory area (in MiB) > before running the test. > > The test is run as follows: ./ksm_tests -P -s 100 > The output: > Total size: 100 MiB > Total time: 0.201106786 s > Average speed: 497.248 MiB/s > > Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com> > --- > v2 -> v3: > - no changes There were no changes to this patch since v2 so my previous review still stands: Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Tyler > > v1 -> v2: > As suggested by Pavel, > - replace MB with MiB > - measure speed more accurately > > Pavel's comments: https://lkml.org/lkml/2021/8/3/1362 > > tools/testing/selftests/vm/ksm_tests.c | 74 ++++++++++++++++++++++++-- > 1 file changed, 70 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c > index cdeb4a028538..432dfe615e50 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 (1ul << 20) > > 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 MiB)\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 MiB)\n"); > > exit(0); > } > @@ -407,6 +414,47 @@ 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; > + unsigned long scan_time_ns; > + > + map_size *= MB; > + > + 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); > + > + printf("Total size: %lu MiB\n", map_size / MB); > + printf("Total time: %ld.%09ld s\n", scan_time_ns / NSEC_PER_SEC, > + scan_time_ns % NSEC_PER_SEC); > + 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 +466,9 @@ 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 +502,12 @@ 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 +519,9 @@ 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 +563,14 @@ 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 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 1/2] selftests: vm: add KSM merging time test 2021-08-19 16:29 ` Tyler Hicks @ 2021-08-20 17:19 ` Pavel Tatashin 0 siblings, 0 replies; 7+ messages in thread From: Pavel Tatashin @ 2021-08-20 17:19 UTC (permalink / raw) To: Tyler Hicks Cc: Zhansaya Bagdauletkyzy, Andrew Morton, linux-mm, linux-kselftest, LKML On Thu, Aug 19, 2021 at 12:29 PM Tyler Hicks <tyhicks@linux.microsoft.com> wrote: > > On 2021-08-19 21:33:41, Zhansaya Bagdauletkyzy 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 MiB/s. User must specify the size of duplicated memory area (in MiB) > > before running the test. > > > > The test is run as follows: ./ksm_tests -P -s 100 > > The output: > > Total size: 100 MiB > > Total time: 0.201106786 s > > Average speed: 497.248 MiB/s > > > > Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com> > > --- > > v2 -> v3: > > - no changes > > There were no changes to this patch since v2 so my previous review still > stands: > > Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Thank you for addressing my comments in v2. Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages 2021-08-19 15:33 [PATCH v3 0/2] add KSM performance tests Zhansaya Bagdauletkyzy 2021-08-19 15:33 ` [PATCH v3 1/2] selftests: vm: add KSM merging time test Zhansaya Bagdauletkyzy @ 2021-08-19 15:33 ` Zhansaya Bagdauletkyzy 2021-08-19 16:31 ` Tyler Hicks 1 sibling, 1 reply; 7+ messages in thread From: Zhansaya Bagdauletkyzy @ 2021-08-19 15:33 UTC (permalink / raw) To: akpm; +Cc: linux-mm, linux-kselftest, linux-kernel, tyhicks, pasha.tatashin Since merged pages are copied every time they need to be modified, the write access time is different between shared and non-shared pages. Add ksm_cow_time() function which evaluates latency of these COW breaks. First, 4000 pages are allocated and the time, required to modify 1 byte in every other page, is measured. After this, the pages are merged into 2000 pairs and in each pair, 1 page is modified (i.e. they are decoupled) to detect COW breaks. The time needed to break COW of merged pages is then compared with performance of non-shared pages. The test is run as follows: ./ksm_tests -C The output: Total size: 15 MiB Not merged pages: Total time: 0.002185489 s Average speed: 3202.945 MiB/s Merged pages: Total time: 0.004386872 s Average speed: 1595.670 MiB/s Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com> --- v2 -> v3: - address Tyler's feedback Tyler's comments: https://lkml.org/lkml/2021/8/16/931 v1 -> v2: As suggested by Pavel, - add baseline figures with non-shared pages - instead of having all pages merged together, create pairs of duplicated pages Pavel's comments: https://lkml.org/lkml/2021/8/3/1363 tools/testing/selftests/vm/ksm_tests.c | 86 +++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c index 432dfe615e50..c14927417759 100644 --- a/tools/testing/selftests/vm/ksm_tests.c +++ b/tools/testing/selftests/vm/ksm_tests.c @@ -33,7 +33,8 @@ enum ksm_test_name { CHECK_KSM_UNMERGE, CHECK_KSM_ZERO_PAGE_MERGE, CHECK_KSM_NUMA_MERGE, - KSM_MERGE_TIME + KSM_MERGE_TIME, + KSM_COW_TIME }; static int ksm_write_sysfs(const char *file_path, unsigned long val) @@ -98,7 +99,8 @@ static void print_help(void) " -U (page unmerging)\n" " -P evaluate merging time and speed.\n" " For this test, the size of duplicated memory area (in MiB)\n" - " must be provided using -s option\n\n"); + " must be provided using -s option\n" + " -C evaluate the time required to break COW of merged pages.\n\n"); printf(" -a: specify the access protections of pages.\n" " <prot> must be of the form [rwx].\n" @@ -455,6 +457,77 @@ static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size) return KSFT_FAIL; } +static int ksm_cow_time(int mapping, int prot, int timeout, size_t page_size) +{ + void *map_ptr; + struct timespec start_time, end_time; + unsigned long cow_time_ns; + + /* page_count must be less than 2*page_size */ + size_t page_count = 4000; + + map_ptr = allocate_memory(NULL, prot, mapping, '*', page_size * page_count); + if (!map_ptr) + return KSFT_FAIL; + + if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) { + perror("clock_gettime"); + return KSFT_FAIL; + } + for (size_t i = 0; i < page_count - 1; i = i + 2) + memset(map_ptr + page_size * i, '-', 1); + if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) { + perror("clock_gettime"); + return KSFT_FAIL; + } + + cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC + + (end_time.tv_nsec - start_time.tv_nsec); + + printf("Total size: %lu MiB\n\n", (page_size * page_count) / MB); + printf("Not merged pages:\n"); + printf("Total time: %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC, + cow_time_ns % NSEC_PER_SEC); + printf("Average speed: %.3f MiB/s\n\n", ((page_size * (page_count / 2)) / MB) / + ((double)cow_time_ns / NSEC_PER_SEC)); + + /* Create 2000 pairs of duplicate pages */ + for (size_t i = 0; i < page_count - 1; i = i + 2) { + memset(map_ptr + page_size * i, '+', i / 2 + 1); + memset(map_ptr + page_size * (i + 1), '+', i / 2 + 1); + } + if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout)) + goto err_out; + + if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) { + perror("clock_gettime"); + goto err_out; + } + for (size_t i = 0; i < page_count - 1; i = i + 2) + memset(map_ptr + page_size * i, '-', 1); + if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) { + perror("clock_gettime"); + goto err_out; + } + + cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC + + (end_time.tv_nsec - start_time.tv_nsec); + + printf("Merged pages:\n"); + printf("Total time: %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC, + cow_time_ns % NSEC_PER_SEC); + printf("Average speed: %.3f MiB/s\n", ((page_size * (page_count / 2)) / MB) / + ((double)cow_time_ns / NSEC_PER_SEC)); + + munmap(map_ptr, page_size * page_count); + return KSFT_PASS; + +err_out: + printf("Not OK\n"); + munmap(map_ptr, page_size * page_count); + return KSFT_FAIL; +} + int main(int argc, char *argv[]) { int ret, opt; @@ -468,7 +541,7 @@ int main(int argc, char *argv[]) bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT; long size_MB = 0; - while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNP")) != -1) { + while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPC")) != -1) { switch (opt) { case 'a': prot = str_to_prot(optarg); @@ -522,6 +595,9 @@ int main(int argc, char *argv[]) case 'P': test_name = KSM_MERGE_TIME; break; + case 'C': + test_name = KSM_COW_TIME; + break; default: return KSFT_FAIL; } @@ -571,6 +647,10 @@ int main(int argc, char *argv[]) ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec, size_MB); break; + case KSM_COW_TIME: + ret = ksm_cow_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec, + page_size); + break; } if (ksm_restore(&ksm_sysfs_old)) { -- 2.25.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages 2021-08-19 15:33 ` [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages Zhansaya Bagdauletkyzy @ 2021-08-19 16:31 ` Tyler Hicks 2021-08-20 17:20 ` Pavel Tatashin 0 siblings, 1 reply; 7+ messages in thread From: Tyler Hicks @ 2021-08-19 16:31 UTC (permalink / raw) To: Zhansaya Bagdauletkyzy Cc: akpm, linux-mm, linux-kselftest, linux-kernel, pasha.tatashin On 2021-08-19 21:33:43, Zhansaya Bagdauletkyzy wrote: > Since merged pages are copied every time they need to be modified, > the write access time is different between shared and non-shared pages. > Add ksm_cow_time() function which evaluates latency of these COW > breaks. First, 4000 pages are allocated and the time, required to modify > 1 byte in every other page, is measured. After this, the pages are > merged into 2000 pairs and in each pair, 1 page is modified (i.e. they > are decoupled) to detect COW breaks. The time needed to break COW of > merged pages is then compared with performance of non-shared pages. > > The test is run as follows: ./ksm_tests -C > The output: > Total size: 15 MiB > > Not merged pages: > Total time: 0.002185489 s > Average speed: 3202.945 MiB/s > > Merged pages: > Total time: 0.004386872 s > Average speed: 1595.670 MiB/s > > Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com> > --- > v2 -> v3: > - address Tyler's feedback Thanks for incorporating my suggestions! I can confirm that my feedback was completely addressed. Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Tyler > > Tyler's comments: https://lkml.org/lkml/2021/8/16/931 > > v1 -> v2: > As suggested by Pavel, > - add baseline figures with non-shared pages > - instead of having all pages merged together, create pairs of > duplicated pages > > Pavel's comments: https://lkml.org/lkml/2021/8/3/1363 > > tools/testing/selftests/vm/ksm_tests.c | 86 +++++++++++++++++++++++++- > 1 file changed, 83 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c > index 432dfe615e50..c14927417759 100644 > --- a/tools/testing/selftests/vm/ksm_tests.c > +++ b/tools/testing/selftests/vm/ksm_tests.c > @@ -33,7 +33,8 @@ enum ksm_test_name { > CHECK_KSM_UNMERGE, > CHECK_KSM_ZERO_PAGE_MERGE, > CHECK_KSM_NUMA_MERGE, > - KSM_MERGE_TIME > + KSM_MERGE_TIME, > + KSM_COW_TIME > }; > > static int ksm_write_sysfs(const char *file_path, unsigned long val) > @@ -98,7 +99,8 @@ static void print_help(void) > " -U (page unmerging)\n" > " -P evaluate merging time and speed.\n" > " For this test, the size of duplicated memory area (in MiB)\n" > - " must be provided using -s option\n\n"); > + " must be provided using -s option\n" > + " -C evaluate the time required to break COW of merged pages.\n\n"); > > printf(" -a: specify the access protections of pages.\n" > " <prot> must be of the form [rwx].\n" > @@ -455,6 +457,77 @@ static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size) > return KSFT_FAIL; > } > > +static int ksm_cow_time(int mapping, int prot, int timeout, size_t page_size) > +{ > + void *map_ptr; > + struct timespec start_time, end_time; > + unsigned long cow_time_ns; > + > + /* page_count must be less than 2*page_size */ > + size_t page_count = 4000; > + > + map_ptr = allocate_memory(NULL, prot, mapping, '*', page_size * page_count); > + if (!map_ptr) > + return KSFT_FAIL; > + > + if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) { > + perror("clock_gettime"); > + return KSFT_FAIL; > + } > + for (size_t i = 0; i < page_count - 1; i = i + 2) > + memset(map_ptr + page_size * i, '-', 1); > + if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) { > + perror("clock_gettime"); > + return KSFT_FAIL; > + } > + > + cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC + > + (end_time.tv_nsec - start_time.tv_nsec); > + > + printf("Total size: %lu MiB\n\n", (page_size * page_count) / MB); > + printf("Not merged pages:\n"); > + printf("Total time: %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC, > + cow_time_ns % NSEC_PER_SEC); > + printf("Average speed: %.3f MiB/s\n\n", ((page_size * (page_count / 2)) / MB) / > + ((double)cow_time_ns / NSEC_PER_SEC)); > + > + /* Create 2000 pairs of duplicate pages */ > + for (size_t i = 0; i < page_count - 1; i = i + 2) { > + memset(map_ptr + page_size * i, '+', i / 2 + 1); > + memset(map_ptr + page_size * (i + 1), '+', i / 2 + 1); > + } > + if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout)) > + goto err_out; > + > + if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) { > + perror("clock_gettime"); > + goto err_out; > + } > + for (size_t i = 0; i < page_count - 1; i = i + 2) > + memset(map_ptr + page_size * i, '-', 1); > + if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) { > + perror("clock_gettime"); > + goto err_out; > + } > + > + cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC + > + (end_time.tv_nsec - start_time.tv_nsec); > + > + printf("Merged pages:\n"); > + printf("Total time: %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC, > + cow_time_ns % NSEC_PER_SEC); > + printf("Average speed: %.3f MiB/s\n", ((page_size * (page_count / 2)) / MB) / > + ((double)cow_time_ns / NSEC_PER_SEC)); > + > + munmap(map_ptr, page_size * page_count); > + return KSFT_PASS; > + > +err_out: > + printf("Not OK\n"); > + munmap(map_ptr, page_size * page_count); > + return KSFT_FAIL; > +} > + > int main(int argc, char *argv[]) > { > int ret, opt; > @@ -468,7 +541,7 @@ int main(int argc, char *argv[]) > bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT; > long size_MB = 0; > > - while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNP")) != -1) { > + while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPC")) != -1) { > switch (opt) { > case 'a': > prot = str_to_prot(optarg); > @@ -522,6 +595,9 @@ int main(int argc, char *argv[]) > case 'P': > test_name = KSM_MERGE_TIME; > break; > + case 'C': > + test_name = KSM_COW_TIME; > + break; > default: > return KSFT_FAIL; > } > @@ -571,6 +647,10 @@ int main(int argc, char *argv[]) > ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec, > size_MB); > break; > + case KSM_COW_TIME: > + ret = ksm_cow_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec, > + page_size); > + break; > } > > if (ksm_restore(&ksm_sysfs_old)) { > -- > 2.25.1 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages 2021-08-19 16:31 ` Tyler Hicks @ 2021-08-20 17:20 ` Pavel Tatashin 0 siblings, 0 replies; 7+ messages in thread From: Pavel Tatashin @ 2021-08-20 17:20 UTC (permalink / raw) To: Tyler Hicks Cc: Zhansaya Bagdauletkyzy, Andrew Morton, linux-mm, linux-kselftest, LKML On Thu, Aug 19, 2021 at 12:31 PM Tyler Hicks <tyhicks@linux.microsoft.com> wrote: > > On 2021-08-19 21:33:43, Zhansaya Bagdauletkyzy wrote: > > Since merged pages are copied every time they need to be modified, > > the write access time is different between shared and non-shared pages. > > Add ksm_cow_time() function which evaluates latency of these COW > > breaks. First, 4000 pages are allocated and the time, required to modify > > 1 byte in every other page, is measured. After this, the pages are > > merged into 2000 pairs and in each pair, 1 page is modified (i.e. they > > are decoupled) to detect COW breaks. The time needed to break COW of > > merged pages is then compared with performance of non-shared pages. > > > > The test is run as follows: ./ksm_tests -C > > The output: > > Total size: 15 MiB > > > > Not merged pages: > > Total time: 0.002185489 s > > Average speed: 3202.945 MiB/s > > > > Merged pages: > > Total time: 0.004386872 s > > Average speed: 1595.670 MiB/s > > > > Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com> > > --- > > v2 -> v3: > > - address Tyler's feedback > > Thanks for incorporating my suggestions! I can confirm that my feedback > was completely addressed. > > Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> > > Tyler Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2021-08-20 17:20 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-08-19 15:33 [PATCH v3 0/2] add KSM performance tests Zhansaya Bagdauletkyzy 2021-08-19 15:33 ` [PATCH v3 1/2] selftests: vm: add KSM merging time test Zhansaya Bagdauletkyzy 2021-08-19 16:29 ` Tyler Hicks 2021-08-20 17:19 ` Pavel Tatashin 2021-08-19 15:33 ` [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages Zhansaya Bagdauletkyzy 2021-08-19 16:31 ` Tyler Hicks 2021-08-20 17:20 ` Pavel Tatashin
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