Re: Illegal use of reserved word in system.h

[Ben Greear]

Lee Revell wrote:
> On Fri, 2005-05-20 at 11:27 +0200, Helge Hafting wrote:
>
> > Ben Greear wrote:
> >
> >
> > > Arjan van de Ven wrote:
> > >
> > >
> > > > HZ may not exist. At all; people are trying to remove it. And userspace
> > > > has no business knowing about it either.
> > >
> > >
> > > It can be helpful to know what HZ you are running at, for instance if 
> > > you care
> > > very much about the (average) precision of a select/poll timeout.
> >
> > Will  knowing it help?  You may find out that you don't have much precision,
> > but then theres nothing to do about it.
>
>
> Yes, it will.  If you have an RT constraint and 10ms won't cut it (say,
> you want to send MIDI clock) then you can use the RTC.

Right.  For instance, before I found the 1000 HZ patch for the 2.4
kernel I would set the RTC to tick 1024 times a second, and then add
that FD to my select() fd-sets.  That causes select to return after about
1ms, and I could do this in a loop to get the X ms of sleep that I needed.

This is not as nice as having a clean 1ms tick clock, but it's a hell of
a lot better than a full busy spin...

Ben

--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com

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