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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-12-10 12:30:23 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-12-12 23:22:18 +0100
commit04dab58a39d402162a7effe7278df8cd41557252 (patch)
tree72ef8dca1e3a3d56bf68ce729678c638dd247e8b /Documentation
parent9456823c842f346c74265fcd98d008d87a7eb6f5 (diff)
downloadlinux-04dab58a39d402162a7effe7278df8cd41557252.tar.bz2
cpuidle: Add 'above' and 'below' idle state metrics
Add two new metrics for CPU idle states, "above" and "below", to count the number of times the given state had been asked for (or entered from the kernel's perspective), but the observed idle duration turned out to be too short or too long for it (respectively). These metrics help to estimate the quality of the CPU idle governor in use. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-devices-system-cpu7
-rw-r--r--Documentation/admin-guide/pm/cpuidle.rst10
2 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 73318225a368..9605dbd4b5b5 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -145,6 +145,8 @@ What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/name
/sys/devices/system/cpu/cpuX/cpuidle/stateN/power
/sys/devices/system/cpu/cpuX/cpuidle/stateN/time
/sys/devices/system/cpu/cpuX/cpuidle/stateN/usage
+ /sys/devices/system/cpu/cpuX/cpuidle/stateN/above
+ /sys/devices/system/cpu/cpuX/cpuidle/stateN/below
Date: September 2007
KernelVersion: v2.6.24
Contact: Linux power management list <linux-pm@vger.kernel.org>
@@ -166,6 +168,11 @@ Description:
usage: (RO) Number of times this state was entered (a count).
+ above: (RO) Number of times this state was entered, but the
+ observed CPU idle duration was too short for it (a count).
+
+ below: (RO) Number of times this state was entered, but the
+ observed CPU idle duration was too long for it (a count).
What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/desc
Date: February 2008
diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst
index 9a34484fd6e4..106379e2619f 100644
--- a/Documentation/admin-guide/pm/cpuidle.rst
+++ b/Documentation/admin-guide/pm/cpuidle.rst
@@ -398,6 +398,16 @@ deeper the (effective) idle state represented by it. Each of them contains
a number of files (attributes) representing the properties of the idle state
object corresponding to it, as follows:
+``above``
+ Total number of times this idle state had been asked for, but the
+ observed idle duration was certainly too short to match its target
+ residency.
+
+``below``
+ Total number of times this idle state had been asked for, but cerainly
+ a deeper idle state would have been a better match for the observed idle
+ duration.
+
``desc``
Description of the idle state.