Hi Ilpo,
On 11/20/2023 3:13 AM, Ilpo Järvinen wrote:
> Callers of get_cbm_mask() are required to pass a string into which the
> capacity bitmask (CBM) is read. Neither CAT nor CMT tests need the
> bitmask as string but just convert it into an unsigned long value.
>
> Another limitation is that the bit mask reader can only read
> .../cbm_mask files.
>
> Generalize the bit mask reading function into get_bit_mask() such that
> it can be used to handle other files besides the .../cbm_mask and
> handles the unsigned long conversion within get_bit_mask() using
> fscanf(). Change get_cbm_mask() to use get_bit_mask() and rename it to
> get_full_cbm() to better indicates what the function does.
"to better indicates" -> "to better indicate"
>
> Also mark cache_type const while at it and remove useless comments that
> are related to processing of CBM bits.
>
> Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> ---
...
> @@ -229,6 +228,32 @@ int get_cbm_mask(char *cache_type, char *cbm_mask)
> return 0;
> }
>
> +/*
> + * get_full_cbm - Get full Cache Bit Mask (CBM)
> + * @cache_type: Cache type as "L2" or "L3"
> + * @mask: Full cache bit mask representing the maximal portion of cache
> + * available for allocation, returned as unsigned long.
> + *
> + * Return: = 0 on success, < 0 on failure.
> + */
> +int get_full_cbm(const char *cache_type, unsigned long *mask)
> +{
> + char cbm_path[PATH_MAX];
> + int ret;
> +
> + if (!cache_type)
> + return -1;
> +
> + snprintf(cbm_path, sizeof(cbm_path), "%s/%s/cbm_mask",
> + INFO_PATH, cache_type);
> +
> + ret = get_bit_mask(cbm_path, mask);
> + if (ret)
> + return -1;
> +
> + return 0;
Can this just be "return get_bit_mask()" ? But actually, I would
like to propose that this also returns a failure if the returned
mask is zero. This would make the code more robust, especially looking
ahead at utility like cache_portion_size() that divides by this full
mask.
Reinette
@@ -93,25 +93,20 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
int ret, pipefd[2], sibling_cpu_no;
unsigned long cache_size = 0;
unsigned long long_mask;
- char cbm_mask[256];
int count_of_bits;
char pipe_message;
size_t span;
- /* Get default cbm mask for L3/L2 cache */
- ret = get_cbm_mask(cache_type, cbm_mask);
+ ret = get_full_cbm(cache_type, &long_mask);
if (ret)
return ret;
- long_mask = strtoul(cbm_mask, NULL, 16);
-
/* Get L3/L2 cache size */
ret = get_cache_size(cpu_no, cache_type, &cache_size);
if (ret)
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)
@@ -75,17 +75,14 @@ int cmt_resctrl_val(int cpu_no, int n, const char * const *benchmark_cmd)
unsigned long cache_size = 0;
unsigned long long_mask;
char *span_str = NULL;
- char cbm_mask[256];
int count_of_bits;
size_t span;
int ret, i;
- ret = get_cbm_mask("L3", cbm_mask);
+ ret = get_full_cbm("L3", &long_mask);
if (ret)
return ret;
- long_mask = strtoul(cbm_mask, NULL, 16);
-
ret = get_cache_size(cpu_no, "L3", &cache_size);
if (ret)
return ret;
@@ -99,7 +99,7 @@ void tests_cleanup(void);
void mbm_test_cleanup(void);
int mba_schemata_change(int cpu_no, const char * const *benchmark_cmd);
void mba_test_cleanup(void);
-int get_cbm_mask(char *cache_type, char *cbm_mask);
+int get_full_cbm(const char *cache_type, unsigned long *mask);
int get_cache_size(int cpu_no, char *cache_type, unsigned long *cache_size);
void ctrlc_handler(int signum, siginfo_t *info, void *ptr);
int signal_handler_register(void);
@@ -196,30 +196,29 @@ int get_cache_size(int cpu_no, char *cache_type, unsigned long *cache_size)
#define CORE_SIBLINGS_PATH "/sys/bus/cpu/devices/cpu"
/*
- * get_cbm_mask - Get cbm mask for given cache
- * @cache_type: Cache level L2/L3
- * @cbm_mask: cbm_mask returned as a string
+ * get_bit_mask - Get bit mask from given file
+ * @filename: File containing the mask
+ * @mask: The bit mask returned as unsigned long
*
* Return: = 0 on success, < 0 on failure.
*/
-int get_cbm_mask(char *cache_type, char *cbm_mask)
+static int get_bit_mask(const char *filename, unsigned long *mask)
{
- char cbm_mask_path[1024];
FILE *fp;
- if (!cbm_mask)
+ if (!filename || !mask)
return -1;
- sprintf(cbm_mask_path, "%s/%s/cbm_mask", INFO_PATH, cache_type);
-
- fp = fopen(cbm_mask_path, "r");
+ fp = fopen(filename, "r");
if (!fp) {
- perror("Failed to open cache level");
-
+ fprintf(stderr, "Failed to open bit mask file '%s': %s\n",
+ filename, strerror(errno));
return -1;
}
- if (fscanf(fp, "%s", cbm_mask) <= 0) {
- perror("Could not get max cbm_mask");
+
+ if (fscanf(fp, "%lx", mask) <= 0) {
+ fprintf(stderr, "Could not read bit mask file '%s': %s\n",
+ filename, strerror(errno));
fclose(fp);
return -1;
@@ -229,6 +228,32 @@ int get_cbm_mask(char *cache_type, char *cbm_mask)
return 0;
}
+/*
+ * get_full_cbm - Get full Cache Bit Mask (CBM)
+ * @cache_type: Cache type as "L2" or "L3"
+ * @mask: Full cache bit mask representing the maximal portion of cache
+ * available for allocation, returned as unsigned long.
+ *
+ * Return: = 0 on success, < 0 on failure.
+ */
+int get_full_cbm(const char *cache_type, unsigned long *mask)
+{
+ char cbm_path[PATH_MAX];
+ int ret;
+
+ if (!cache_type)
+ return -1;
+
+ snprintf(cbm_path, sizeof(cbm_path), "%s/%s/cbm_mask",
+ INFO_PATH, cache_type);
+
+ ret = get_bit_mask(cbm_path, mask);
+ if (ret)
+ return -1;
+
+ return 0;
+}
+
/*
* get_core_sibling - Get sibling core id from the same socket for given CPU
* @cpu_no: CPU number