[PATCH] iocost_monitor: start from the oldest usage index

[Chengming Zhou]

iocg usage_idx is the latest usage index, we should start from the
oldest usage index to show the consecutive NR_USAGE_SLOTS usages.

Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
 tools/cgroup/iocost_monitor.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/cgroup/iocost_monitor.py b/tools/cgroup/iocost_monitor.py
index 3c21de88af9e..f4699f9b46ba 100644
--- a/tools/cgroup/iocost_monitor.py
+++ b/tools/cgroup/iocost_monitor.py
@@ -173,7 +173,7 @@ class IocgStat:
         self.usages = []
         self.usage = 0
         for i in range(NR_USAGE_SLOTS):
-            usage = iocg.usages[(usage_idx + i) % NR_USAGE_SLOTS].value_()
+            usage = iocg.usages[(usage_idx + 1 + i) % NR_USAGE_SLOTS].value_()
             upct = usage * 100 / HWEIGHT_WHOLE
             self.usages.append(upct)
             self.usage = max(self.usage, upct)
-- 
2.20.1