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

Martin J. Bligh
2005-07-08T23:04:05Z

> It's been over two weeks and nobody has complained about anything.
>
>>
>> > [PATCH] i386: Selectable Frequency of the Timer Interrupt
>>
>> [...]
>>
>> > +choice
>> > + prompt "Timer frequency"
>> > + default HZ_250
>>
>> WHAT?
>>
>> The previous value here i386 is 1000 --- so why is the default 250.
>
> Because 1000 is too high.
>
>> Now that this has hit mainline please consider applying:
>
> We might indeed do that. But if nobody continues to notice anything, we
> might not. We'll see.

I noticed something ... the fact that elapsed times on kernel compiles
etc got significantly faster with lower HZ values ... see for example

http://ftp.kernel.org/pub/linux/kernel/people/mbligh/abat/perf/kernbench.elm3b67.png

Sorry, it's getting a bit scrunched in there ... I need to make it bigger
and filter old details stuff out better.

I think we're talking between 2.6.12-git5 and 2.6.12-git6 right? I can
confirm more explicitly if really need be. 48s -> 45.5s elapsed.

M.