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Date: Fri, 3 Nov 1995 21:42:52 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199511031042.VAA00204@godzilla.zeta.org.au>
To: bde@zeta.org.au, wollman@lcs.mit.edu
Subject: Re: Time problems
Cc: current@FreeBSD.org
Sender: owner-current@FreeBSD.org
Precedence: bulk

>Here is a program that I have used to measure a whole bunch of things
>about the clock...

I get the following output for `rtprio 0 ./thisprog' on a lightly loaded
DX2/66 VLB (ISA clock :-() system running -current:

	min 13, max 171, mean 14.286634, std 1.836667
	1th: 14 (1053245 observations)
	2th: 15 (587593 observations)
	3th: 13 (299847 observations)
	4th: 16 (51817 observations)
	5th: 33 (934 observations)

This is the expected behaviour.

After reducing N from 2000000 to 100000,
I get the following output for `./thisprog' on a heavily loaded
DX2/66 VLB (ISA clock :-() system running Linux 1.2.13:

	Segmentation fault

>#define N 2000000

>int diffs[N];
>int hist[N];

hist[] has indices min..max, not 0..N-1.  max was abour 230000 under
Linux, so an index was out of bounds because I reduced N.  min might be
< 0 if gettimeofday() is broken.

Bruce