[性能優化] CPU電源管理pstate cstate

 

CPU的電源管理是會影響性能的。

pstate指CPU忙時的電源管理，為了省電會調節主頻和電壓。cstate是cpu閑時的電壓管理。

 

詳細資料見：

https://software.intel.com/en-us/blogs/2008/05/29/what-exactly-is-a-p-state-pt-1

https://www.thomas-krenn.com/en/wiki/Processor_P-states_and_C-states

【加星】https://software.intel.com/en-us/articles/power-management-states-p-states-c-states-and-package-c-states

 

linux與kernel如何針對電源管理進行調度：

https://www.kernel.org/doc/html/v4.12/admin-guide/kernel-parameters.html

https://www.kernel.org/doc/html/v4.12/admin-guide/pm/cpufreq.html

https://www.kernel.org/doc/html/v4.12/admin-guide/pm/intel_pstate.html

 

最簡單的，直接關掉它的方法：（見紅字）

intel_pstate=disable intel_idle.max_cstate=0 processor.max_cstate=0

[root@tong ~]# cat /proc/cmdline 
BOOT_IMAGE=/vmlinuz-3.10.0-693.21.4.el7.x86_64 root=UUID=027f3098-783a-491a-9b1a-4d78a910952a ro crashkernel=auto isolcpus=1,4,6,17,20,22 intel_pstate=disable intel_idle.max_cstate=0 processor.max_cstate=0 rhgb quiet