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

Lee Revell
2005-07-11T20:28:15Z

On Mon, 2005-07-11 at 11:38 -0700, Martin J. Bligh wrote:
> That's a very subjective viewpoint. Realize that this is a balancing
> act between latency and overhead ... and you're firmly only looking
> at one side of the argument, instead of taking a comprimise in the
> middle ...
>
> If I start arguing for 100HZ on the grounds that it's much more efficient,
> will that make 250/300 look much better to you? ;-)

Mostly my argument is that all technical arguments aside, it's crazy to
change this in the middle of a stable kernel series.

My other objection is that 90% of the arguments for HZ=250 are based on
battery life. But most Linux systems still don't run on batteries, so I
object to having to take a performance hit (a latency hit, which is the
same as performance for multimedia apps) for their sake.

Tickless + sub HZ timers is a win for everyone, the multimedia people
get better latency, and the laptop people get to run longer.

I guess CONFIG_HZ makes sense if the tickless solutions are not going to
be ready anytime soon. But I don't see the problem with leaving the
default at 1000HZ and letting the laptop users lower it.

Lee