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From: ast@cs.vu.nl (Andy Tanenbaum)
Newsgroups: comp.os.minix
Subject: Re: Disk performance under Minix
Message-ID: <3076@ast.cs.vu.nl>
Date: 25 Aug 89 22:02:17 GMT
References: <21978@louie.udel.EDU> <2141@ditsyda.oz>
Reply-To: ast@cs.vu.nl (Andy Tanenbaum)
Organization: VU Informatica, Amsterdam
Lines: 17

In article <2141@ditsyda.oz> evans@ditsyda.mq.oz (Bruce Evans) writes:
>Some more reference points for fwriting 256K on Minix
>
>cpu		disk		O/S	stdio	cache	real	user	sys
>8088/4.77	3:1/80ms	1.4b-	1.3	 30K#	 81.0	58.5	 9.5
>8088/4.77	3:1/80ms	1.4b-	mine	 30K#	 22.0	 0.2	10.8

These two measurements seem to suggest that a factor of four can be won
by improving stdio.  That package was written by one of my students who
was enthusiastic but not very experienced.  What did you do to stdio to get
this big gain?

I would MUCH prefer a solution that gives good but not optimal performance
by fixing stdio than one that adds a lot of complexity to the kernel
(multiple read aheads etc.)

Andy Tanenbaum (ast@cs.vu.nl)