I've heard some rumors that with values of HZ much larger
than that you're going to have to start recompiling some
utility programs (at least older ones) which were written
assuming the 100Hz was a constant within the third tablet
Moses brought down from the mountain. But these were only
rumors and probably urban legends.
Norm
----- Original Message -----
From: Wayne E. Van Loon Sr. <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, October 13, 2001 1:46 PM
Subject: Re: [rtl] Help on real time scheduling
> Norm and Chunky:
> On 2.2 kernels, I edit
/usr/src/linux/include/asm-i386/param.h
> I usually change the #define HZ to 1000
>
> I also edit the BogoMIPS printk() line in
> /usr/src/linux/init/main.c calibrate_delay()
> to print out the HZ so that a look at dmesg will tell me
what time-slice
> a disk is running.
> I also recompile all modules - anything that might use
jiffys.
>
> Best regards
> Wayne
>
> Chunky Kibbles wrote:
> >
> > On Fri, Oct 12, 2001 at 12:24:00PM -0400, Dresner,
Norman A. wrote:
> > > You're probably using a computer with an x86
architecture. AFAIK, every
> > > Linux implementation except the Alpha CPU uses a
clock rate (jiffies) of 100
> > > Hz or 10 ms; the Alpha uses 1 Khz. Your choices
then are:
> > > 1. Use an Alpha with normal Linux and hope for
the best
> > > 2. Use Real-Time Linux (RTLinux) on any
platform it's been ported
> > > to.
> >
> > Hang on.
> >
> > Aren't jiffies worked out at boot-time, or is that only
because I've
> > only read the source for the x86?
> >
> > I'm sure I remember linux doing some timing loops to
discover
> > BogoMips, then working out how big a jiffy is from
there?
> >
> > [Note: I _would_ read the source, except my machine
went out of
> > contention and now I'm on a friend's box that's only
windows]
> >
> > Gary (-;
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