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

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

Hi Moren,

Thanks for your revew.

在 2024/3/20 22:05, Morten Brørup 写道:
>> From: Huisong Li [mailto:lihuisong@huawei.com]
>> Sent: Wednesday, 20 March 2024 11.55
>>
>> The system-wide CPU latency QoS limit has a positive impact on the idle
>> state selection in cpuidle governor.
>>
>> Linux creates a cpu_dma_latency device under '/dev' directory to obtain the
>> CPU latency QoS limit on system and send the QoS request for userspace.
>> Please see the PM QoS framework in the following link:
>> https://docs.kernel.org/power/pm_qos_interface.html?highlight=qos
>> This feature is supported by kernel-v2.6.25.
>>
>> 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.
>>
>> So this series introduce PM QoS interface.
> This looks like a 1:1 wrapper for a Linux kernel feature.
right
> Does Windows or BSD offer something similar?
How do we know Windows or BSD support this similar feature?
The DPDK power lib just work on Linux according to the meson.build under 
lib/power.
If they support this features, they can open it.
>
> Furthermore, any high-res timing should use nanoseconds, not microseconds or milliseconds.
> I realize that the Linux kernel only uses microseconds for these APIs, but the DPDK API should use nanoseconds.
Nanoseconds is more precise, it's good.
But DPDK API how use nanoseconds as you said the the Linux kernel only 
uses microseconds for these APIs.
Kernel interface just know an integer value with microseconds unit.

/BR
/Huisong