diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c
index f42d4ba70363..8842d379e886 100644
--- a/tools/testing/selftests/resctrl/mba_test.c
+++ b/tools/testing/selftests/resctrl/mba_test.c
@@ -12,7 +12,7 @@
 
 #define RESULT_FILE_NAME	"result_mba"
 #define NUM_OF_RUNS		5
-#define MAX_DIFF		300
+#define MAX_DIFF_PERCENT	5
 #define ALLOCATION_MAX		100
 #define ALLOCATION_MIN		10
 #define ALLOCATION_STEP		10
@@ -62,7 +62,8 @@ static void show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc)
 	     allocation++) {
 		unsigned long avg_bw_imc, avg_bw_resc;
 		unsigned long sum_bw_imc = 0, sum_bw_resc = 0;
-		unsigned long avg_diff;
+		int avg_diff_per;
+		float avg_diff;
 
 		/*
 		 * The first run is discarded due to inaccurate value from
@@ -76,16 +77,19 @@ static void show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc)
 
 		avg_bw_imc = sum_bw_imc / (NUM_OF_RUNS - 1);
 		avg_bw_resc = sum_bw_resc / (NUM_OF_RUNS - 1);
-		avg_diff = labs((long)(avg_bw_resc - avg_bw_imc));
+		avg_diff = (float)labs(avg_bw_resc - avg_bw_imc) / avg_bw_imc;
+		avg_diff_per = (int)(avg_diff * 100);
 
-		ksft_print_msg("%s MBA schemata percentage %u smaller than %d %%\n",
-			       avg_diff > MAX_DIFF ? "Fail:" : "Pass:",
-			       ALLOCATION_MAX - ALLOCATION_STEP * allocation,
-			       MAX_DIFF);
-		ksft_print_msg("avg_diff: %lu\n", avg_diff);
+		ksft_print_msg("%s MBA: diff within %d%% for schemata %u\n",
+			       avg_diff_per > MAX_DIFF_PERCENT ?
+			       "Fail:" : "Pass:",
+			       MAX_DIFF_PERCENT,
+			       ALLOCATION_MAX - ALLOCATION_STEP * allocation);
+
+		ksft_print_msg("avg_diff_per: %d%%\n", avg_diff_per);
 		ksft_print_msg("avg_bw_imc: %lu\n", avg_bw_imc);
 		ksft_print_msg("avg_bw_resc: %lu\n", avg_bw_resc);
-		if (avg_diff > MAX_DIFF)
+		if (avg_diff_per > MAX_DIFF_PERCENT)
 			failed = true;
 	}
 
diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c
index 0d65ba4b62b4..651d4ac15986 100644
--- a/tools/testing/selftests/resctrl/mbm_test.c
+++ b/tools/testing/selftests/resctrl/mbm_test.c
@@ -11,7 +11,7 @@
 #include "resctrl.h"
 
 #define RESULT_FILE_NAME	"result_mbm"
-#define MAX_DIFF		300
+#define MAX_DIFF_PERCENT	5
 #define NUM_OF_RUNS		5
 
 static int
@@ -19,8 +19,8 @@ show_bw_info(unsigned long *bw_imc, unsigned long *bw_resc, int span)
 {
 	unsigned long avg_bw_imc = 0, avg_bw_resc = 0;
 	unsigned long sum_bw_imc = 0, sum_bw_resc = 0;
-	long avg_diff = 0;
-	int runs, ret;
+	int runs, ret, avg_diff_per;
+	float avg_diff = 0;
 
 	/*
 	 * Discard the first value which is inaccurate due to monitoring setup
@@ -33,12 +33,13 @@ show_bw_info(unsigned long *bw_imc, unsigned long *bw_resc, int span)
 
 	avg_bw_imc = sum_bw_imc / 4;
 	avg_bw_resc = sum_bw_resc / 4;
-	avg_diff = avg_bw_resc - avg_bw_imc;
+	avg_diff = (float)labs(avg_bw_resc - avg_bw_imc) / avg_bw_imc;
+	avg_diff_per = (int)(avg_diff * 100);
 
-	ret = labs(avg_diff) > MAX_DIFF;
+	ret = avg_diff_per > MAX_DIFF_PERCENT;
 	ksft_print_msg("%s MBM: diff within %d%%\n",
-		       ret ? "Fail:" : "Pass:", MAX_DIFF);
-	ksft_print_msg("avg_diff: %lu\n", labs(avg_diff));
+		       ret ? "Fail:" : "Pass:", MAX_DIFF_PERCENT);
+	ksft_print_msg("avg_diff_per: %d%%\n", avg_diff_per);
 	ksft_print_msg("Span (MB): %d\n", span);
 	ksft_print_msg("avg_bw_imc: %lu\n", avg_bw_imc);
 	ksft_print_msg("avg_bw_resc: %lu\n", avg_bw_resc);