Re: [PATCH v10 0/2] power: introduce PM QoS interface

["lihuisong (C)" <lihuisong@huawei.com>]

在 2024/10/14 23:27, Stephen Hemminger 写道:
> On Thu, 12 Sep 2024 10:38:10 +0800
> Huisong Li <lihuisong@huawei.com> wrote:
>
>> The deeper the idle state, the lower the power consumption, but the longer
>> the resume time. Some service are delay sensitive and very except the low
>> resume time, like interrupt packet receiving mode.
>>
>> And the "/sys/devices/system/cpu/cpuX/power/pm_qos_resume_latency_us" sysfs
>> interface is used to set and get the resume latency limit on the cpuX for
>> userspace. Please see the description in kernel document[1].
>> Each cpuidle governor in Linux select which idle state to enter based on
>> this CPU resume latency in their idle task.
>>
>> The per-CPU PM QoS API can be used to control this CPU's idle state
>> selection and limit just enter the shallowest idle state to low the delay
>> after sleep by setting strict resume latency (zero value).
>>
>> [1] https://www.kernel.org/doc/html/latest/admin-guide/abi-testing.html?highlight=pm_qos_resume_latency_us#abi-sys-devices-power-pm-qos-resume-latency-us
>
> This is not a direct critique of this patch.
> The power library should have been designed to take a single configuration structure
> specifying CPU frequencies, wake up latency, and all the parameters from the kernel.
> And there would be a simple API with: rte_power_config_set() and rte_power_config_get().
Agreed. There are several different configuration objects in power library.
It would be better if we could put the relevant configurations together.
This may be able to do it after Sivaprasad's optimized patches for core 
and uncore codes in power library.
>
> .