Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!amdcad!ames!hao!noao!arizona!rupley
From: rupley@arizona.edu (John Rupley)
Newsgroups: comp.unix.xenix
Subject: Re: malloc weirdness on Microport System V/AT
Message-ID: <2562@megaron.arizona.edu>
Date: Mon, 26-Oct-87 13:30:20 EST
Article-I.D.: megaron.2562
Posted: Mon Oct 26 13:30:20 1987
Date-Received: Wed, 28-Oct-87 06:51:52 EST
References: <4299@well.UUCP>
Organization: U of Arizona CS Dept, Tucson
Lines: 79
Keywords: malloc swapping Microport
Summary: Problem with Microport malloc verified

In article <4299@well.UUCP>, johnl@well.UUCP (John A. Limpert) writes:
> I have noticed something odd with malloc on microport.  When I run
> a programs that does alot of malloc calls that allocate relatively
> small chunks of memory, the program gets swapped to disk at a very
> high rate.  This seems to start once a certain amount of memory has
> been allocated.  It commonly occurs when I edit large files with
> MicroEMACS or when running pathalias.  My machine has about 2.7 MB

I have found the same problem, under microport sysV/AT.2.2, 
and sent a bug report to microport.  No response.  I would be
grateful for any help.  Is the problem "unfixable", ie tied
to the Intel segmented architecture?

For anyone who wants to verify the malloc problem, the 
following code shows it.



John Rupley
uucp: ...!ihnp4!arizona!rupley
voice: 602-325-4533

****************cut here************************

# To unbundle, sh this file
echo unbundling makefile 1>&2
cat >makefile <<'AlBeRtEiNsTeIn'
CFLAGS=		-Ml 

maltst:		maltst.o
		cc $(CFLAGS) maltst.o -o malloc.test
		size malloc.test
AlBeRtEiNsTeIn
echo unbundling maltst.c 1>&2
cat >maltst.c <<'AlBeRtEiNsTeIn'
/*
malloc.test.c

test of malloc for large files

problem-- after about 300 kbytes of allocation, the system behaves oddly:
	ps shows no valid text pointer and a "growing" process
		
things seem stranger when compiled with malloc library
*/

#include <stdio.h>
#include <malloc.h>

main(argc, argv)
int argc;
char **argv;
{
	extern void exit();
	extern char *malloc();
	
	char *lp;
	unsigned limit;
	unsigned i;
	unsigned size;

	if (argc < 3)
	{
		printf("usage: %s   malloc_size  number_of_mallocs\n", argv[0]);
		exit(-1);
	}
	
	size = (unsigned )atoi(argv[1]);
	limit = (unsigned )atoi(argv[2]);
	printf("\n\n");
	for (i = 0; i < limit; i++)
	{
		lp = malloc(size);
		printf("lp = %lx    bytes = %ld\r", lp, (long )((i+1)*size));
	}
	printf("\n\n");
	exit(1);
}
AlBeRtEiNsTeIn