Commands Reference, Volume 4

pmcycles Command

Purpose

Measures processor clock speed.

Syntax

pmcycles [ -d] [ -m]

Description

The pmcycles command uses the Performance Monitor cycle counter and the processor real-time clock to measure the actual processor clock speed in MHz. Optionally, it also displays the decrementer speed in MHz and nanoseconds per tick. The decrementer is a binary counter which generates a clock interrupt each time the clock goes to zero. The tick is the value of a decrement. On some machines, time is decremented in nanoseconds, so each tick is equal to one nanosecond. On other machines, the value of the decrement depends on the machine.

This command is only supported on processors supported by bos.pmapi.

Flags

Examples

1. To display the processor speed, type:

   pmcycles

   Output similar to the following appears:

   This machine runs at 133 MHz

2. To display each processor speed, type:

   pmcycles -m

   Output similar to the following appears:

   Cpu 0 runs at 200 MHz
   CPU 1 runs at 200 MHz

Related Information

pm_cycles subroutine.