The /proc/cpuinfo File

/proc/cpuinfo is a short, read-only, plain text file that contains information about the CPUs (central processing units) on a computer.

It can easily be read with a command such as cat, i.e.,

cat /proc/cpuinfo

If a computer contains two or more CPUs, the information about each is separated by a blank line. The information about each processor consists of a set of lines (18 on Red Hat 9), each of which contains a key word followed by a separator (consisting of spaces, a colon and then another space) and then by a value. Each key word can be any combination of alphanumeric, underscore and space characters.

Only a few of the lines contain information that is meaningful to most users. Among them are processor (the value of which is zero for single-processor systems), vendor_id (the value of which is GenuineIntel in the case of an Intel processor), cpu family, model_name, cpu MHz (processor speed in millions of cycles per second), cache size (the amount of high speed cache memory built into the processor) and fpu (the value of which is yes if the processor contains a floating point unit).

The flags field shows which features are available in the CPU; this information is of interest only to users with an in-depth knowledge of processors. The final item, bogomips, is a Linux-specific measurement of the CPU's speed in MIPS (millions of instructions per second) while not performing any actual work; it is not an accurate indicator of overall processor speed and is only used for some testing purposes.

Created February 22, 2006.
Copyright © 2006 The Linux Information Project. All Rights Reserved.