6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
commit ef43c30858754d99373a63dff33280a9969b49bc upstream.
The initial value of 5% chosen for the maximum allowed percentage
difference between resctrl mbm value and IMC mbm value in
commit 06bd03a57f8c ("selftests/resctrl: Fix MBA/MBM results reporting
format") was "randomly chosen value" (as admitted by the changelog).
When running tests in our lab across a large number platforms, 5%
difference upper bound for success seems a bit on the low side for the
MBA and MBM tests. Some platforms produce outliers that are slightly
above that, typically 6-7%, which leads MBA/MBM test frequently
failing.
Replace the "randomly chosen value" with a success bound that is based
on those measurements across large number of platforms by relaxing the
MBA/MBM success bound to 8%. The relaxed bound removes the failures due
the frequent outliers.
Fixed commit description style error during merge:
Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Fixes: 06bd03a57f8c ("selftests/resctrl: Fix MBA/MBM results reporting format")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Tested-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/resctrl/mba_test.c | 2 +-
tools/testing/selftests/resctrl/mbm_test.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- 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_PERCENT 5
+#define MAX_DIFF_PERCENT 8
#define ALLOCATION_MAX 100
#define ALLOCATION_MIN 10
#define ALLOCATION_STEP 10
--- 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_PERCENT 5
+#define MAX_DIFF_PERCENT 8
#define NUM_OF_RUNS 5
static int
