Subject: Re: How to kill NetBSD-Sparc without really trying
To: None <MLARKIN@CSUPomona.Edu, port-sparc@NetBSD.ORG>
From: James Graham - Systems Anarchist <jgraham@defender.VAS.viewlogic.com>
List: port-sparc
Date: 02/15/1996 15:25:03
I think there's a similar condition which occurs when trying to apply the
XFree86 SPARC patches to the X11R6 distribution -- specifically the
font10 patch.

The only thing I still had running was that the tty would still respond
to a ^T (stty status), and there was a LOT of stuff still running.

MLARKIN@CSUPomona.Edu sez:
/*
 * 
 * 
 * I succeeded in killing my IPC last night running 1.1A. I wasn't really trying
 * to load down the system, but an errant process got out of line and went on
 * a malloc() swarm (or so it appeared). 
 * 
 * What happens to the system if a process tries to allocate little pieces of
 * memory hundreds, thousands, millions of times?
 * 
 * The program I was running was a Gauss-Legendre approximation of pi. Calculating
 * the value of pi to 1,048,576 digits (2^20) was mentioned as taking 13-15 mb
 * of ram for this particular run. I have 12mb physical in the IPC, but I've never had much problems running processes that need more ram (ie, swap). The swap
 * device is configured as a 48mb scrap partition.
 * 
 * About 30 seconds into the run, the system froze completely, after consistently 
 * getting slower and slower. All attempts to stop the runaway process failed. 
 * 
 * I had a systat:vmstat running in another window, and watched the pi program
 * eat 7mb before the vmstat was shut out completely. 
 * 
 * Thinking I could "ride it out" , I left the process running for a few hours,
 * the disk thrashing to all hell. Finally, everything stopped. No brain activity.
 * Clinical system death.
 * 
 * Any clues as to how a simple (?) usermode program could eat up all the ram and
 * not cause a seg viol. ? Or kernel termination at the very least. Some sort of
 * graceful exit. 
 * 
 * 
 * I have the source to the pi program if someone wants to duplicate this e
 * error.
 * 
 * -mlml
 * 
 */





				--*greywolf;
--
I want to upgrade my system from Solaris 2.0 to 4.4 BSD.