On Thu, 12 Sep 2024 10:38:10 +0800 Huisong Li <lihuis...@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().
