CAT test doesn't take shareable bits into account, i.e., the test might be sharing cache with some devices (e.g., graphics).
Introduce get_mask_no_shareable() and use it to provision an environment for CAT test where the allocated LLC is isolated better.
Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com --- tools/testing/selftests/resctrl/cat_test.c | 2 +- tools/testing/selftests/resctrl/resctrl.h | 3 ++ tools/testing/selftests/resctrl/resctrlfs.c | 56 +++++++++++++++++++++ 3 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index a1834dd5ad9a..e2d10124cdb1 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -100,7 +100,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type) cache_size = 0;
/* Get default cbm mask for L3/L2 cache */ - ret = get_cbm_mask(cache_type, &long_mask); + ret = get_mask_no_shareable(cache_type, &long_mask); if (ret) return ret; count_of_bits = count_consecutive_bits(long_mask, NULL); diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index aa5dc8b95a06..be5a61e7fbcc 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -106,8 +106,11 @@ void tests_cleanup(void); void mbm_test_cleanup(void); int mba_schemata_change(int cpu_no, char *bw_report, char **benchmark_cmd); void mba_test_cleanup(void); +unsigned long create_bit_mask(unsigned int start, unsigned int len); unsigned int count_consecutive_bits(unsigned long val, unsigned int *start); int get_cbm_mask(char *cache_type, unsigned long *mask); +int get_shareable_mask(char *cache_type, unsigned long *shareable_mask); +int get_mask_no_shareable(char *cache_type, unsigned long *mask); int get_cache_size(int cpu_no, char *cache_type, unsigned long *cache_size); int cache_alloc_size(int cpu_no, char *cache_type, unsigned long alloc_mask, unsigned long *alloc_size); diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index 4efaf69c8152..94b99b06bc89 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -220,6 +220,16 @@ static int get_bit_mask(char *filename, unsigned long *mask) return 0; }
+/* + * create_bit_mask- Create bit mask from start,len pair + * @start: LSB of the mask + * @len Number of bits in the mask + */ +unsigned long create_bit_mask(unsigned int start, unsigned int len) +{ + return ((1UL << len) - 1UL) << start; +} + /* * count_consecutive_bits - Returns the longest train of bits in a bit mask * @val A bit mask @@ -273,6 +283,52 @@ int get_cbm_mask(char *cache_type, unsigned long *mask) return 0; }
+/* + * get_shareable_mask - Get shareable mask from shareable_bits for given cache + * @cache_type: Cache level L2/L3 + * @shareable_mask: shareable mask returned as unsigned long + * + * Return: = 0 on success, < 0 on failure. + */ +int get_shareable_mask(char *cache_type, unsigned long *shareable_mask) +{ + char mask_path[1024]; + + if (!cache_type) + return -1; + + snprintf(mask_path, sizeof(mask_path), "%s/%s/shareable_bits", + INFO_PATH, cache_type); + + return get_bit_mask(mask_path, shareable_mask); +} + +/* + * get_mask_no_shareable - Get CBM mask without shareable_bits for given cache + * @cache_type: Cache level L2/L3 + * @mask: mask returned as unsigned long + * + * Return: = 0 on success, < 0 on failure. + */ +int get_mask_no_shareable(char *cache_type, unsigned long *mask) +{ + unsigned long full_mask, shareable_mask; + unsigned int start, len; + + if (get_cbm_mask(cache_type, &full_mask) < 0) + return -1; + if (get_shareable_mask(cache_type, &shareable_mask) < 0) + return -1; + + len = count_consecutive_bits(full_mask & ~shareable_mask, &start); + if (!len) + return -1; + + *mask = create_bit_mask(start, len); + + return 0; +} + /* * get_core_sibling - Get sibling core id from the same socket for given CPU * @cpu_no: CPU number