Hi Ilpo,
> CAT and CMT tests depends on masks being continuous.
>
> Replace count_bits with more appropriate variant that counts consecutive bits.
>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/resctrl/cat_test.c | 6 ++---
> tools/testing/selftests/resctrl/cmt_test.c | 3 +--
> tools/testing/selftests/resctrl/resctrl.h | 1 +
> tools/testing/selftests/resctrl/resctrlfs.c | 30
> +++++++++++++++++++++
> 4 files changed, 34 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/resctrl/cat_test.c
> b/tools/testing/selftests/resctrl/cat_test.c
> index d3fbd4de9f8a..a1834dd5ad9a 100644
> --- a/tools/testing/selftests/resctrl/cat_test.c
> +++ b/tools/testing/selftests/resctrl/cat_test.c
> @@ -78,7 +78,7 @@ static int check_results(struct resctrl_val_param *param)
> }
>
> fclose(fp);
> - no_of_bits = count_bits(param->mask);
> + no_of_bits = count_consecutive_bits(param->mask, NULL);
>
> return show_cache_info(sum_llc_perf_miss, no_of_bits,
> param->span / 64,
> MAX_DIFF, MAX_DIFF_PERCENT,
> NUM_OF_RUNS, @@ -103,6 +103,7 @@ int cat_perf_miss_val(int cpu_no, int
> n, char *cache_type)
> ret = get_cbm_mask(cache_type, &long_mask);
> if (ret)
> return ret;
> + count_of_bits = count_consecutive_bits(long_mask, NULL);
>
> /* Get L3/L2 cache size */
> ret = get_cache_size(cpu_no, cache_type, &cache_size); @@ -110,9
> +111,6 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
> return ret;
> ksft_print_msg("Cache size :%lu\n", cache_size);
>
> - /* Get max number of bits from default-cabm mask */
> - count_of_bits = count_bits(long_mask);
> -
> if (!n)
> n = count_of_bits / 2;
>
> diff --git a/tools/testing/selftests/resctrl/cmt_test.c
> b/tools/testing/selftests/resctrl/cmt_test.c
> index efe77e0f1d4c..98e7d3accd73 100644
> --- a/tools/testing/selftests/resctrl/cmt_test.c
> +++ b/tools/testing/selftests/resctrl/cmt_test.c
> @@ -84,14 +84,13 @@ int cmt_resctrl_val(int cpu_no, int n, char
> **benchmark_cmd)
> ret = get_cbm_mask("L3", &long_mask);
> if (ret)
> return ret;
> + count_of_bits = count_consecutive_bits(long_mask, NULL);
>
> ret = get_cache_size(cpu_no, "L3", &cache_size);
> if (ret)
> return ret;
> ksft_print_msg("Cache size :%lu\n", cache_size);
>
> - count_of_bits = count_bits(long_mask);
> -
> if (n < 1 || n > count_of_bits) {
> ksft_print_msg("Invalid input value for numbr_of_bits n!\n");
> ksft_print_msg("Please enter value in range 1 to %d\n",
> count_of_bits); diff --git a/tools/testing/selftests/resctrl/resctrl.h
> b/tools/testing/selftests/resctrl/resctrl.h
> index 65425d92684e..aa5dc8b95a06 100644
> --- a/tools/testing/selftests/resctrl/resctrl.h
> +++ b/tools/testing/selftests/resctrl/resctrl.h
> @@ -106,6 +106,7 @@ 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 int count_consecutive_bits(unsigned long val, unsigned int
> +*start);
> int get_cbm_mask(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,
> diff --git a/tools/testing/selftests/resctrl/resctrlfs.c
> b/tools/testing/selftests/resctrl/resctrlfs.c
> index f01ecfa64063..4efaf69c8152 100644
> --- a/tools/testing/selftests/resctrl/resctrlfs.c
> +++ b/tools/testing/selftests/resctrl/resctrlfs.c
> @@ -10,6 +10,8 @@
> */
> #include "resctrl.h"
>
> +#include <strings.h>
> +
> static int find_resctrl_mount(char *buffer) {
> FILE *mounts;
> @@ -218,6 +220,34 @@ static int get_bit_mask(char *filename, unsigned long
> *mask)
> return 0;
> }
>
> +/*
> + * count_consecutive_bits - Returns the longest train of bits in a bit mask
> + * @val A bit mask
> + * @start The location of the least-significant bit of the longest train
> + *
> + * Return: The length of the consecutive bits in the longest train of bits
> + */
> +unsigned int count_consecutive_bits(unsigned long val, unsigned int
> +*start) {
> + unsigned long last_val;
> + int count = 0;
> +
> + while (val) {
> + last_val = val;
> + val &= (val >> 1);
> + count++;
> + }
There may not be a case that the most-significant bit is 1 at present,
but if this case exists, it cannot count correctly.
Best regards,
Shaopeng TAN
