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Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!swrinde!cs.utexas.edu!uunet!decwrl!decwrl!usenet.coe.montana.edu!bsd.coe.montana.edu!nate From: nate@bsd.coe.montana.edu (Nate Williams) Newsgroups: comp.os.386bsd.questions Subject: Re: Disk Thrashing question Date: 28 Sep 1993 01:39:14 GMT Organization: Montana Stateu University, Bozeman MT Lines: 58 Message-ID: <2884k2$d9k@pdq.coe.montana.edu> References: <1993Sep27.170443.444@doug.cae.wisc.edu> NNTP-Posting-Host: bsd.coe.montana.edu In article <1993Sep27.170443.444@doug.cae.wisc.edu>, John Edward Tillema <tillemaj@cae.wisc.edu> wrote: > > > I have had FreeBSD running for about a month or so on my 486 >now, and have noticed one major disadvantage to it compared to Linux >(at least for me). It seems to take virtually nothing to cause me >to start swapping like crazy, and even hang the system. My setup is: >8 Meg Ram, 17 Meg swap space, 486/33, 340 Meg drive, with 300 for Unix. ^^^^^^^^^ >If i run anything in the background, or compile one program, or sun >a comm program, you can hear the disk swapping like crazy and performance >really drops(you can easily type a line of text before the first character >is printed). I can even hang the system. I found a good way of doing >this is the following: > run olvwm. > run XV and view a gif (or jpg, or probably anything), not necessarily > large, the last one was only 200k. > run emacs and load in a large file, here I'm talking about a 7 meg file. With X running (2 - 3 MB), and xv (probably 1 MB with the image displayed) the system (2 MB in memory) AND emacs ( 1 MB for emacs + 7 MB for the file you're editing ) you've used up more space than you have available. Now, since emacs brings everything into memory, there is nothing you can do about using up all your memory, and Linux *should* act the exact same way since emacs == emacs == emacs when it comes to GNU emacs. >The result I get is that it brings the emacs window up, and then all disk >activity stops, the mouse doesn't respond, and there is no way to abort >aside from a reboot of the system. Basically, you've got processes competing for available memory space, most notably emacs. >In Linux, things would get slow, but >never like that, and it never hung like that either, the only crashes I had >was when running X+openwin in 8 megs w/o swap. I have narrowed down the >FreeBSD kernel so that it only has devices I use (eg. got rid of the SCSI >stuff). Is this to be expected? I wouldn't think so. I am mildly suprised that Linux handles running out of memory better, especially after hearing some of the horror stories that happen when Linux runs out of memory. I suppose it's possible that you are also running out of swap space. A way to check that is to run swapinfo in another xterm when you start up emacs, and see what state your system is in. Nate -- nate@bsd.coe.montana.edu | Freely available *nix clones benefit everyone, nate@cs.montana.edu | so let's not compete with each other, let's work #: (406) 994-4836 | compete with folks who try to tie us down to home #: (406) 586-0579 | proprietary O.S.'s (Microsloth) - Me