Stephan Meyer (
Sat, 1 Mar 1997 22:13:47 +0100 (MET)

Absolutely. All you need to do is set the correct permissions on /dev/msr,
e.g.: crw-r--r--

The cycle counter is register number 0x10

cheers, Stephan

On Sat, 1 Mar 1997 wrote:
> Is it possible for me to use the cycle counter MSR entirely from user
> space? I hack a simulation application that uses the cycle counter on
> the SGI. The advantage to using the cycle counter is that it serves
> as a super fast, super accurate gettimeofday. This is important to my
> simulation. It would be nice if I could get the same kind of
> advantage on Linux/i386.
> FYI: Already, this application benchmarks better on a Pentium Pro 200
> than on a 195MHz r10000 SGI Indigo2. And the SGI has the unfair
> advantage of not having to byte swap a lot of network traffic and
> having a cycle counter.
> --
> Gene McCulley

Stephan Meyer