[PATCH v3 08/21] selftests/resctrl: Ensure sibling CPU is not same as original CPU

Fenghua Yu
2020-10-20T23:51:40Z

From: Reinette Chatre <reinette.chatre@intel.com>

The resctrl tests can accept a CPU on which the tests are run and use
default of CPU #1 if it is not provided. In the CAT test a "sibling CPU"
is determined that is from the same package where another thread will be
run.

The current algorithm with which a "sibling CPU" is determined does not
take the provided/default CPU into account and when that CPU is the
first CPU in a package then the "sibling CPU" will be selected to be the
same CPU since it starts by picking the first CPU from core_siblings_list.

Fix the "sibling CPU" selection by taking the provided/default CPU into
account and ensuring a sibling that is a different CPU is selected.

Fixes: 78941183d1b1 ("selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
tools/testing/selftests/resctrl/resctrlfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index 67d775d03271..05956319d9ce 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -268,7 +268,7 @@ int get_core_sibling(int cpu_no)
while (token) {
sibling_cpu_no = atoi(token);
/* Skipping core 0 as we don't want to run test on core 0 */
- if (sibling_cpu_no != 0)
+ if (sibling_cpu_no != 0 && sibling_cpu_no != cpu_no)
break;
token = strtok(NULL, "-,");
}
--
2.29.0