[RFC v4 0/5] Report percentage of time in hardware sleep state

From: Mario Limonciello
Date: Thu Nov 17 2022 - 17:58:39 EST


Sven van Ashbrook brought a patch to the kernel mailing list that
attempted to change the reporting level of a s0ix entry issue to a
different debugging level so that infastructure used by Google could
better scan logs to catch problems.

This approach was rejected, but during the conversation another
suggestion was made by David E. Box to introduce some infrastructure
into the kernel to report this information.

One idea suggested in RFC v3 was to report the percentage of time instead
of the raw numbers. This allows the details to how much time to be reported
to be abstracted by individual drivers instead.

RFC v3->v4:
* Switch to percentage reporting
* More changes to Intel drivers to hopefully report this properly.

Mario Limonciello (5):
PM: Add a sysfs file to represent the percentage of sleep in hardware
state
platform/x86/amd: pmc: Report duration of time in deepest hw state
platform/x86/intel/pmc: core: Drop check_counters
platform/x86/intel/pmc: core: Always capture counters on suspend
platform/x86/intel/pmc: core: Report duration of time in HW sleep
state

Documentation/ABI/testing/sysfs-power | 9 +++++++
drivers/platform/x86/amd/pmc.c | 5 ++--
drivers/platform/x86/intel/pmc/core.c | 13 +++-------
drivers/platform/x86/intel/pmc/core.h | 1 -
include/linux/suspend.h | 2 ++
include/linux/timekeeping.h | 1 +
kernel/power/main.c | 36 +++++++++++++++++++++++++++
kernel/time/timekeeping.c | 20 ++++++++++++---
8 files changed, 70 insertions(+), 17 deletions(-)

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2.34.1