张锐-Intel Low Power Mode Daemon on Hybrid CPUs.pdf

1、Intel Low Power Mode Daemon on Hybrid CPUsZhang Rui Open Source Operating System Annual Technical Conference 20242Backgroud-Hybrid CPUs multiple CPU types within the same processor Different CPUs have different power efficiencies Power save can be achieved by running tasks on a set of most power eff

2、icient CPUs only(Low Power Mode)Open Source Operating System Annual Technical Conference 20243Low Power Mode on Hybrid CPUs(MTL)PcoreL2L2L2L3EcoreCompute Die(Die C6)L2LcoreTTSoC Die(Active)Open Source Operating System Annual Technical Conference 20244Intel Low Power Mode Daemon Diagramintel_lpmd/pro

3、c/statIntel_lpmd corethermaldintel_hfiGnome Power settingsirqbalance/proc/irq/systemd cgroup cpusetsisolated cpuset PartitionOS/Kernel InterfaceXml config fileOpen Source Operating System Annual Technical Conference 20245Xml Config file lp_mode_cpus mode Performance/Balance/Powersave Def HfiLpmEnabl

4、e util_entry_threshold util_exit_thresholdOpen Source Operating System Annual Technical Conference 20246ChallengesPower gain depends on how quiet the non-LPM CPUs are cgroup cpuset controller allows restricting tasks to run on certain CPUs system cgroup cpuset cgroup isolated partitionOpen Source Op

5、erating System Annual Technical Conference 20247Challenge:Idle Load Balance on isolated CPUsOpen Source Operating System Annual Technical Conference 20248Challenge:Timers fired on isolated CPUsOpen Source Operating System Annual Technical Conference 20249Challenges fast response polling hurts power

6、firmware work load type interrupts helps to LPM exit only irq placement irqbalance(socket message)takes time to respond or need to handle a large number of irq procfs entriesOpen Source Operating System Annual Technical Conference 202410Ref