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From: michaelv@iastate.edu (Michael L. VanLoon)
Newsgroups: comp.os.386bsd.questions,comp.os.386bsd.misc
Subject: Re: Whats wrong with Linux networking ???
Date: 15 Aug 94 06:11:17 GMT
Organization: Iowa State University, Ames, Iowa
Lines: 33
Message-ID: <michaelv.776931077@ponderous.cc.iastate.edu>
References: <RSANDERS.94Aug9003813@hrothgar.mindspring.com> <1994Aug13.012953.5809@cs.brown.edu> <32jp2u$bpb@Starbase.NeoSoft.COM> <32ll52$n7d@quagga.ru.ac.za> <1994Aug15.034939.20997@cs.brown.edu>
NNTP-Posting-Host: ponderous.cc.iastate.edu
In <1994Aug15.034939.20997@cs.brown.edu> mhw@cs.brown.edu (Mark Weaver) writes:
>Typically running X, compiling, and perhaps dragging around xterms
>or reading manual pages at the same time. To be honest, I'm not
>exactly sure that it's thrashing, but I get one hell of a lot of
>disk activity. I always get significant disk activity from compiling,
>even though my /tmp is a ramdisk.
>On Linux, while doing the same thing, there is hardly any disk
>activity at all. I always think something's wrong when compiling
>under Linux because I don't hear the characteristic disk chattering
>that I associate with compiling.
Actually, what you're experiencing might not be VM swapage at all, but
rather synchronous writes to disk. From what I understand, from other
posts on this subject, Linux delays writing everything to disk until
buffers get flushed. Whereas *BSD always writes superblock/inode/
whatever data immediately to disk, and only delays writing actual data
blocks until buffers flush. This causes *BSD to be a little slower in
asynchronous disk benchmarks and such, but causes it to trash the
drive much less severely if your machine were to crash, say, in the
middle of a large compile.
Just a theory... and all "facts" pulled from my convoluted memory
from prior discussions on this subject...
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Michael L. VanLoon Iowa State University Computation Center
michaelv@iastate.edu Project Vincent Systems Staff
Free your mind and your machine -- NetBSD free Un*x for PC/Mac/Amiga/etc.
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