Date:	Mon, 11 May 92 23:52:57 -0400
From:	ressler AT cs DOT cornell DOT edu (Gene Ressler)
To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Subject:	gcc `hanging' with disk light on
Status:	O

I am not a heavy user of gcc for big jobs, but
did do some experiments to see how the paging
mechanism behaves.  I have a tiny program that
builds a balanced binary search tree on-line 
from sorted input.  My machine is 486/33
210 Mb 18ms IDE, 8Mb XMS.  For a tree of final
size ~12 megs, I get real thrashing
as soon as it hits ~8Mb.  I.e., to build a
7Mb tree takes ~8 seconds.  To build the
12 meg tree takes almost 20 _minutes_ with the
drive light on constantly.  This is with either
DOS 5 smartdrv or Hyperdisk at 1.5 megs.

Perhaps at least some of the disk `hang' problems
being reported are such thrashing.  I haven't looked
at go32 to see what the replacement strategy is,
but I wouldn't expect this program to give degenerate
behavior with LRU.

Gene

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