Re: sysconf (was Re: RLIM_INFINITY inconsistency between archs)

From: H. Peter Anvin (hpa@transmeta.com)
Date: Tue Aug 01 2000 - 11:19:23 EST


David Woodhouse wrote:
>
> hpa@zytor.com said:
> > I don't think we want to do this! IMO, HZ should not get exported to
> > user space *AT ALL*. Instead, for the few interfaces that need it,
> > we'll export a "user space HZ" (USER_HZ) which is fixed. No need for
> > a kernel hack. When we support nonstandard values for HZ, we need to
> > fix the few interfaces that actually export jiffies values to convert
> > from "user jiffies" to real jiffies.
>
> No. Why do the arithmetic in the kernel when we could just export the raw
> data, with full accuracy, and let user-space sort it out?

Because HZ may be different from kernel to kernel, or even runtime changeable.

> User-space may want to know the value of HZ for other reasons anyway.
>
> if (HZ < 1000) {
> perror("You must hack your kernel to improve scheduling latency");
> exit(1);
> }

GACK!!! Save us from such user-space idiocy!

        -hpa

-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt

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