Documentation: Document sysfs interfaces purr, spurr, idle_purr, idle_spurr

Add documentation for the following sysfs interfaces:
/sys/devices/system/cpu/cpuX/purr
/sys/devices/system/cpu/cpuX/spurr
/sys/devices/system/cpu/cpuX/idle_purr
/sys/devices/system/cpu/cpuX/idle_spurr

Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1586249263-14048-6-git-send-email-ego@linux.vnet.ibm.com

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 2e0e3b4..b73b8b5 100644 (file)
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -580,3 +580,42 @@ Description:       Secure Virtual Machine
                If 1, it means the system is using the Protected Execution
                Facility in POWER9 and newer processors. i.e., it is a Secure
                Virtual Machine.
+
+What:          /sys/devices/system/cpu/cpuX/purr
+Date:          Apr 2005
+Contact:       Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
+Description:   PURR ticks for this CPU since the system boot.
+
+               The Processor Utilization Resources Register (PURR) is
+               a 64-bit counter which provides an estimate of the
+               resources used by the CPU thread. The contents of this
+               register increases monotonically. This sysfs interface
+               exposes the number of PURR ticks for cpuX.
+
+What:          /sys/devices/system/cpu/cpuX/spurr
+Date:          Dec 2006
+Contact:       Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
+Description:   SPURR ticks for this CPU since the system boot.
+
+               The Scaled Processor Utilization Resources Register
+               (SPURR) is a 64-bit counter that provides a frequency
+               invariant estimate of the resources used by the CPU
+               thread. The contents of this register increases
+               monotonically. This sysfs interface exposes the number
+               of SPURR ticks for cpuX.
+
+What:          /sys/devices/system/cpu/cpuX/idle_purr
+Date:          Apr 2020
+Contact:       Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
+Description:   PURR ticks for cpuX when it was idle.
+
+               This sysfs interface exposes the number of PURR ticks
+               for cpuX when it was idle.
+
+What:          /sys/devices/system/cpu/cpuX/idle_spurr
+Date:          Apr 2020
+Contact:       Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
+Description:   SPURR ticks for cpuX when it was idle.
+
+               This sysfs interface exposes the number of SPURR ticks
+               for cpuX when it was idle.