diff options
| author | Chanwoo Choi <cw00.choi@samsung.com> | 2020-07-02 20:41:28 +0900 |
|---|---|---|
| committer | Chanwoo Choi <cw00.choi@samsung.com> | 2020-07-30 17:22:57 +0900 |
| commit | 4dc3bab8687f1ea11322611de6d4138b43eccdcd (patch) | |
| tree | 92562bc8fe71300245c09cc7e29935126ca4a691 /Documentation | |
| parent | ed279529754d0c94115de5317e369d25468547c9 (diff) | |
PM / devfreq: Add support delayed timer for polling mode
Until now, the devfreq driver using polling mode like simple_ondemand
governor have used only deferrable timer for reducing the redundant
power consumption. It reduces the CPU wake-up from idle due to polling mode
which check the status of Non-CPU device.
But, it has a problem for Non-CPU device like DMC device with DMA operation.
Some Non-CPU device need to do monitor continuously regardless of CPU state
in order to decide the proper next status of Non-CPU device.
So, add support the delayed timer for polling mode to support
the repetitive monitoring. The devfreq driver and user can select
the kind of timer on either deferrable and delayed timer.
For example, change the timer type of DMC device
based on Exynos5422-based Odroid-XU3 as following:
- If want to use deferrable timer as following:
echo deferrable > /sys/class/devfreq/10c20000.memory-controller/timer
- If want to use delayed timer as following:
echo delayed > /sys/class/devfreq/10c20000.memory-controller/timer
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-devfreq | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq index 9758eb85ade3..deefffb3bbe4 100644 --- a/Documentation/ABI/testing/sysfs-class-devfreq +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -108,3 +108,15 @@ Description: frequency requested by governors and min_freq. The max_freq overrides min_freq because max_freq may be used to throttle devices to avoid overheating. + +What: /sys/class/devfreq/.../timer +Date: July 2020 +Contact: Chanwoo Choi <cw00.choi@samsung.com> +Description: + This ABI shows and stores the kind of work timer by users. + This work timer is used by devfreq workqueue in order to + monitor the device status such as utilization. The user + can change the work timer on runtime according to their demand + as following: + echo deferrable > /sys/class/devfreq/.../timer + echo delayed > /sys/class/devfreq/.../timer |