[PATCH 05/24] selftests/resctrl: Create cache_size() helper

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

CAT and CMT tests calculate the span size from the n-bits cache
allocation on their own.

Add cache_size() helper which calculates size of the cache portion for
the given number of bits and use it to replace the existing span
calculations. This also prepares for the new CAT test that will need to
determine the size of the cache portion also during results processing.

cache_size local variables were renamed out of the way to
cache_total_size.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 tools/testing/selftests/resctrl/cat_test.c | 10 +++++-----
 tools/testing/selftests/resctrl/cmt_test.c |  8 ++++----
 tools/testing/selftests/resctrl/resctrl.h  | 14 ++++++++++++++
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index 4852bbda2e71..80861c362a53 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -91,7 +91,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 {
 	unsigned long l_mask, l_mask_1;
 	int ret, pipefd[2], sibling_cpu_no;
-	unsigned long cache_size = 0;
+	unsigned long cache_total_size = 0;
 	unsigned long long_mask;
 	int count_of_bits;
 	char pipe_message;
@@ -103,10 +103,10 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 		return ret;
 
 	/* Get L3/L2 cache size */
-	ret = get_cache_size(cpu_no, cache_type, &cache_size);
+	ret = get_cache_size(cpu_no, cache_type, &cache_total_size);
 	if (ret)
 		return ret;
-	ksft_print_msg("Cache size :%lu\n", cache_size);
+	ksft_print_msg("Cache size :%lu\n", cache_total_size);
 
 	/* Get max number of bits from default-cabm mask */
 	count_of_bits = count_bits(long_mask);
@@ -138,7 +138,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 	/* Set param values for parent thread which will be allocated bitmask
 	 * with (max_bits - n) bits
 	 */
-	span = cache_size * (count_of_bits - n) / count_of_bits;
+	span = cache_size(cache_total_size, l_mask, long_mask);
 	strcpy(param.ctrlgrp, "c2");
 	strcpy(param.mongrp, "m2");
 	strcpy(param.filename, RESULT_FILE_NAME2);
@@ -160,7 +160,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 		param.mask = l_mask_1;
 		strcpy(param.ctrlgrp, "c1");
 		strcpy(param.mongrp, "m1");
-		span = cache_size * n / count_of_bits;
+		span = cache_size(cache_total_size, l_mask_1, long_mask);
 		strcpy(param.filename, RESULT_FILE_NAME1);
 		param.num_of_runs = 0;
 		param.cpu_no = sibling_cpu_no;
diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
index a6c79edc33cd..e8997ff5bc04 100644
--- a/tools/testing/selftests/resctrl/cmt_test.c
+++ b/tools/testing/selftests/resctrl/cmt_test.c
@@ -72,7 +72,7 @@ int cmt_resctrl_val(int cpu_no, int n, const char * const *benchmark_cmd)
 {
 	const char * const *cmd = benchmark_cmd;
 	const char *new_cmd[BENCHMARK_ARGS];
-	unsigned long cache_size = 0;
+	unsigned long cache_total_size = 0;
 	unsigned long long_mask;
 	char *span_str = NULL;
 	int count_of_bits;
@@ -83,10 +83,10 @@ int cmt_resctrl_val(int cpu_no, int n, const char * const *benchmark_cmd)
 	if (ret)
 		return ret;
 
-	ret = get_cache_size(cpu_no, "L3", &cache_size);
+	ret = get_cache_size(cpu_no, "L3", &cache_total_size);
 	if (ret)
 		return ret;
-	ksft_print_msg("Cache size :%lu\n", cache_size);
+	ksft_print_msg("Cache size :%lu\n", cache_total_size);
 
 	count_of_bits = count_bits(long_mask);
 
@@ -107,7 +107,7 @@ int cmt_resctrl_val(int cpu_no, int n, const char * const *benchmark_cmd)
 		.setup		= cmt_setup,
 	};
 
-	span = cache_size * n / count_of_bits;
+	span = cache_size(cache_total_size, param.mask, long_mask);
 
 	if (strcmp(cmd[0], "fill_buf") == 0) {
 		/* Duplicate the command to be able to replace span in it */
diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
index 2f3f0ee439d8..da06b2d492f9 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -117,4 +117,18 @@ int show_cache_info(unsigned long sum_llc_val, int no_of_bits,
 		    unsigned long max_diff_percent, unsigned long num_of_runs,
 		    bool platform, bool cmt);
 
+/*
+ * cache_size - Calculate the size of a cache portion
+ * @cache_size:	Cache size in bytes
+ * @mask:	Cache portion mask
+ * @cache_mask:	Full bitmask for the cache
+ *
+ * Return: The size of the cache portion in bytes.
+ */
+static inline int cache_size(unsigned long cache_size, unsigned long mask,
+			     unsigned long cache_mask)
+{
+	return cache_size * count_bits(mask) / count_bits(cache_mask);
+}
+
 #endif /* RESCTRL_H */
-- 
2.30.2