diff mbox series

[v2,6/6] selftests/resctrl: Reduce failures due to outliers in MBA/MBM tests

Message ID 20230915154438.82931-7-ilpo.jarvinen@linux.intel.com
State Superseded
Headers show
Series selftests/resctrl: Fixes to failing tests | expand

Commit Message

Ilpo Järvinen Sept. 15, 2023, 3:44 p.m. UTC
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.

Fixes: 06bd03a57f8c ("selftests/resctrl: Fix MBA/MBM results reporting format")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 tools/testing/selftests/resctrl/mba_test.c | 2 +-
 tools/testing/selftests/resctrl/mbm_test.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Comments

Reinette Chatre Sept. 26, 2023, 9:41 p.m. UTC | #1
Hi Ilpo,

On 9/15/2023 8:44 AM, Ilpo Järvinen wrote:
> 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.
> 
> Fixes: 06bd03a57f8c ("selftests/resctrl: Fix MBA/MBM results reporting format")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Thank you.

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Reinette
diff mbox series

Patch

diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c
index cf8284dadcb2..d3bf4368341e 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_PERCENT	5
+#define MAX_DIFF_PERCENT	8
 #define ALLOCATION_MAX		100
 #define ALLOCATION_MIN		10
 #define ALLOCATION_STEP		10
diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c
index 1ae131a2e246..d3c0d30c676a 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_PERCENT	5
+#define MAX_DIFF_PERCENT	8
 #define NUM_OF_RUNS		5
 
 static int