Re: Why HZ on i386 is 100 ?

Helge Hafting
2002-04-17T07:55:18Z

David Mosberger wrote:

> The last time I measured timer tick overhead on ia64 it was well below
> 1% of overhead. I don't really like using kernel builds as a
> benchmark, because there are far too many variables for the results to
> have any long-term or cross-platform value. But since it's popular, I
> did measure it quickly on a relatively slow (old) Itanium box: with
> 100Hz, the kernel compile was about 0.6% faster than with 1024Hz
> (2.4.18 UP kernel).

Did you try a parallell build, with the number of processes at least
2-3 times the number of processors? Then you get more
of the cache-miss effects from switching processes, not
merely the overhead of the fairly fast scheduler.

Helge Hafting