Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt.

Joe Korty
2005-05-17T13:45:12Z

On Mon, May 16, 2005 at 10:31:25PM -0700, Christoph Lameter wrote:
> + help
> + 100 HZ is a typical choice for servers, SMP and NUMA systems
> + with lots of processors that may show reduced performance if
> + too many timer interrupts are occurring.

One of the options should mention the power savings benefit on laptops.
How about:

help

100 HZ, the lowest setting, is the best choice for any system
where the servicing of interrupts is expensive. This includes:
systems with so many processors that the mere execution of timer
interrupts on each and every processor degrades performance,
virtual systems, where Linux is not running on bare hardware
but is instead a guest operating system running on top of a
virtualization layer, and laptops, where each interrupt causes
a processor that is in low power mode to power up in order
to service the interrupt, and after the interrupt is complete,
might take up to one millisecond to power back down again.

Regards,
Joe
--
"Money can buy bandwidth, but latency is forever" -- John Mashey