Re: [PATCH] HZ: 300Hz support

From: Willy Tarreau
Date: Wed Nov 08 2006 - 17:40:01 EST


On Wed, Nov 08, 2006 at 08:42:37PM +0000, Alan Cox wrote:
> Fix two things. Firstly the unit is "Hz" not "HZ". Secondly it is useful
> to have 300Hz support when doing multimedia work. 250 is fine for us in
> Europe but the US frame rate is 30fps (29.99 blah for pedants). 300
> gives us a tick divisible by both 25 and 30, and for interlace work 50
> and 60. It's also giving similar performance to 250Hz.
>
> I'd argue we should remove 250 and add 300, but that might be excess
> disruption for now.

I'd like to keep 250 for a simple reason : the period is an integer
number of milliseconds. I find it very convenient to be able to convert
jiffies to ms. It serves at several places, for instance, poll(). In
fact, what I like with 250 is that there is no divide between ms and
jiffies, but just a bit shift.

Regards,
Willy

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