Different host running modes may enable the host to proactively reduce the CPU frequency when the service is not busy, thereby reducing power consumption. However, when the service load is light, the lower CPU frequency affects the performance of interaction between the host and storage device and increases the host I/O latency. Therefore, if you are concerned about the latency performance under light load, you can configure the host running mode to ensure that the CPU frequency is not reduced and achieve the optimal performance.
On a Linux host, run cat /proc/cpuinfo to view the CPU clock frequency.
To ensure that the CPU clock frequency does not decrease, configure the host running mode as follows:
Step 1 Run cd to enter the /sys/devices/system/cpu/ directory.
Step 2 Run ll to view the number of CPUs in the /sys/devices/system/cpu directory.
Step 3 Run echo performance for each CPU in the /sys/devices/system/cpu/ directory.
linux-ob3a:~ # cd /sys/devices/system/cpu
linux-ob3a:/sys/devices/system/cpu # ll
total 0
drwxr-xr-x 7 root root 0 May 25 08:35 cpu0
drwxr-xr-x 7 root root 0 May 25 08:35 cpu1
drwxr-xr-x 7 root root 0 May 25 08:35 cpu10
drwxr-xr-x 7 root root 0 May 25 08:35 cpu11
drwxr-xr-x 7 root root 0 May 25 08:35 cpu2
drwxr-xr-x 7 root root 0 May 25 08:35 cpu3
drwxr-xr-x 7 root root 0 May 25 08:35 cpu4
drwxr-xr-x 7 root root 0 May 25 08:35 cpu5
drwxr-xr-x 7 root root 0 May 25 08:35 cpu6
drwxr-xr-x 7 root root 0 May 25 08:35 cpu7
drwxr-xr-x 7 root root 0 May 25 08:35 cpu8
drwxr-xr-x 7 root root 0 May 25 08:35 cpu9
drwxr-xr-x 3 root root 0 May 28 14:43 cpufreq
drwxr-xr-x 2 root root 0 May 28 14:43 cpuidle
-r--r--r-- 1 root root 4096 May 25 08:35 kernel_max
-r--r--r-- 1 root root 4096 May 28 14:43 offline
-r--r--r-- 1 root root 4096 May 25 08:35 online
-r--r--r-- 1 root root 4096 May 28 14:43 possible
-r--r--r-- 1 root root 4096 May 28 14:43 present
--w------- 1 root root 4096 May 28 14:43 probe
--w------- 1 root root 4096 May 28 14:43 release
-rw-r--r-- 1 root root 4096 May 28 14:43 sched_mc_power_savings
-rw-r--r-- 1 root root 4096 May 28 14:43 sched_smt_power_savings
linux-ob3a:/sys/devices/system/cpu # echo performance > cpu0/cpufreq/scaling_governor
