KernelTrap: Robert Love Explains Variable HZ

[ Thanks to Jeremy
for this link. ]

“Robert Love recently backported the jiffies_to_clock_t() code
from the 2.5 development kernel to the 2.4 stable kernel. This
patch allows one to adjust the frequency of the timer interrupt,
defined in the standard 2.4 kernel with HZ=100. In 2.5 this has
been increased to HZ=1000.

“I wrote Robert asking if he could explain the usefulness of his
patch, and he replied in kind with a lengthy and very interesting
email detailing what the patch is, how it works, and why it’s
useful. He explains, ‘The timer interrupt is at the heart of the
system. Everything lives and dies based on it. Its period is
basically the granularity of the system: timers hit on 10ms
intervals, timeslices come due at 10ms intervals, etc.’

“Read on to learn what affect changing this value will have on
your Linux server, and to see the actual patch…”


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