I have an old Lenovo ThinkStation P500 with a Xeon E5-2670v3 CPU. inxi shows that its freq range is 1.2G~3.1G.
bruin@debian:/sys/bus$ inxi -C
CPU: Info: 12-Core model: Intel Xeon E5-2670 v3 bits: 64 type: MT MCP L2 cache: 30 MiB
Speed: 2594 MHz min/max: 1200/3100 MHz Core speeds (MHz): 1: 2594 2: 2594 3: 2594 4: 2594 5: 2594 6: 2594 7: 2594
8: 2594 9: 2594 10: 2594 11: 2594 12: 2594 13: 2594 14: 2594 15: 2594 16: 2594 17: 2594 18: 2594 19: 2594 20: 2594
21: 2594 22: 2594 23: 2594 24: 2594
But when I running spec2017 to stress test the CPU, each core is running at about 2.6G (instead of 3.1G as I expected).
Also, as tested, sudo cpupower frequency-set -f 3.1G does not help. However, if the freuquency specified on the command line is lower than 2.6G, the command takes effect as reflectec in output of /proc/cpuinfo, values above 2.6G seems having no effect.
I am wondering what's the reason for that, and how to let the CPU goes to its maximum frequency under stress test?
btw, I am currently running Debian 11.3.
答案1
Your CPU is rated for 2.6GHz as it's "nominal" peak clock speed.
Per Intel ARK: Intel® Xeon® Processor E5-2670
CPU Specifications Processor Base Frequency 2.60 GHz
The 3.3GHz is a "Turbo" speed that is dependent on power and thermal budgets and is not guaranteed to be available all the time. It depends on the task being run and may only be available when only 1 core is in use.
CPU Specifications Max Turbo Frequency 3.30 GHz
2.6GHz is effectively the "100%" duty CPU speed, not 3.3GHz. As far as I know there is no way to permanently force the CPU to operate in Turbo Boost without actually overclocking it. Turbo Boost simply lets the CPU clock itself higher to increase performance without any input from the OS.
Turbo Boost speeds (i.e. speeds above 2.6GHz) are at the discretion of the hardware and are simply a "you are allowed to boost if you can" on/off switch, they are not actively selected by the Kernel.