how to find cpu frequency in linux ?

Frequency

CPU frequency scaling enables the operating system to scale the CPU frequency up or down in order to save power. CPU frequencies can be scaled automatically depending on the system load, in response to ACPI events, or manually by userspace programs.

CPU frequency scaling is implemented in the Linux kernel, the infrastructure is called cpufreq

The frequency/speed of the processor is reported by both lscpu and /proc/cpuinfo.

Method 1:

lscpu | grep -i mhz

Example :

ravi@linuxforfreshers.com:~$ lscpu | grep -i mhz

CPU MHz:               1596.000

Method 2:

cat /proc/cpuinfo | grep -i mhz | uniq

Example:

ravi@linuxforfreshers.com:~$ cat /proc/cpuinfo | grep -i mhz | uniq

cpu MHz                      : 1596.000

Method 3:

The change of frequency can be seen by monitoring the output of /proc/cpuinfo using watch.

$ watch -n 0.1 "cat /proc/cpuinfo | grep -i mhz"

Method 4:

Using lshw command

Example:

ravi@linuxforfreshers.com:~$ sudo lshw -c cpu | grep capacity

       capacity: 1596MHz

Method 5:

Using dmidecode

Example:

ravi@linuxforfreshers.com:~$ sudo dmidecode -t processor | grep "Speed"

            Max Speed: 6000 MHz

            Current Speed: 2133 MHz

You can also get the current cpu frequency with this command:

cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

Note : root access required using this command.

Example :

ravi@linuxforfreshers.com:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

2133000