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Date: Sat, 4 Sep 2004 10:23:44 -0700 (PDT)
From: Matthew Dillon <dillon@apollo.backplane.com>
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To: Don Lewis <truckman@FreeBSD.org>
References: <200409040709.i8479U79031043@gw.catspoiler.org>
cc: freebsd-current@FreeBSD.org
Subject: Re: what is fsck's "slowdown"?
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:This sort of thing was my initial thought, but the posted CPU usage
:statistics show that fsck is burning up most of its CPU cycles in
:userland.
:
:>> load: 0.99  cmd: fsck 67 [running] 15192.26u 142.30s 99% 184284k
:
:Increasing MAXBUFSPACE looks like it would make the problem worse
:because getdatablk() does a linear search.

    Oh my. I  didn't even notice.  That code dates all the way back to 1994
    so I wont bash the author too badly, but it is pretty aweful coding.

    Hashing the buffer cache is trivial.  I'll do it for DragonFly and post
    the patch as a template for you guys to do it in FreeBSD (or you could just
    do it on your own, it really does look trivial).

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>