Path: utzoo!utgpu!water!watmath!egisin
From: egisin@watmath.waterloo.edu (Eric Gisin)
Newsgroups: comp.os.minix
Subject: Re: Speed of execution related to chmem value !?!
Keywords: fix chmem time memory
Message-ID: <17859@watmath.waterloo.edu>
Date: 28 Mar 88 19:40:45 GMT
References: <7616@nswitgould.OZ>
Organization: U of Waterloo, Ontario
Lines: 13

In article <7616@nswitgould.OZ>, nick@nswitgould.OZ (Nick Andrew) writes:
> 
> 	I'm very puzzled by the behavior of the Minix Fix program. When run
> with a stack+malloc size of 3000 bytes, Fix runs extremely slowly. When run
> with an additional 3000 bytes to play around with, Fix runs TEN times as
> fast. [ Background: Minix 1.2, using 1.2 lib & 1.1 compiler ]
> 
This was a common problem with large programs on V7 too.

The program fopen's a file.
Fopen cannot malloc a buffer because it cannot expand the data segment.
So fopen leaves the file unbuffered, and everything gets read/written
one byte at a time. That's why you see the high system time.