Date: Wed, 16 Sep 1998 09:25:55 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Mike Smith <mike@smith.net.au> Cc: joelh@gnu.org, Terry Lambert <tlambert@primenet.com>, tom@uniserve.com, gpalmer@FreeBSD.ORG, irc@cooltime.simplenet.com, freebsd-current@FreeBSD.ORG Subject: Re: Download of FreeBSD 3.0-SNAP Message-ID: <3346.905930755@critter.freebsd.dk> In-Reply-To: Your message of "Wed, 16 Sep 1998 00:24:19 PDT." <199809160724.AAA00684@word.smith.net.au>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <199809160724.AAA00684@word.smith.net.au>, Mike Smith writes: >> In message <199809152258.PAA01641@dingo.cdrom.com>, Mike Smith writes: >> >> >> Without knowing the true geometry of the disk (which I assume EIDE >> >> doesn't allow), we can't optimize for the cylinder patterns anyway, so >> >> I suppose it's a moot issue. I suppose that by manually specifying >> >> the geometry at format time then it could be slightly optimized for >> >> those hdd's that come with true geometry. Was that taken out because >> >> the computation was outweighing the seek time benefits, or what? >> > >> >Disk geometry is nonlinear, and the calculations involved in optimising >> >for it are complex and not really compatible with the optimisations for >> >this sort of thing already part of the filesystem. >> >> ... Which have been disabled since 2.0.5 or something, we're now running >> on a pseudo geometry which fails horribly on huge disks. > >It's better than what we'd have otherwise. > >> According to Kirk, 16 to 32 is the right number of cylinder groups, >> all over 50 is waste. we can end up with 200+ cgs on modern disks :-( > >Yay, even less locality of reference. You were paying attention to the >thread on inode allocation policies that went past just recently? No, I don't recall so, it must have been on a list I'm not on. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." "ttyv0" -- What UNIX calls a $20K state-of-the-art, 3D, hi-res color terminal To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3346.905930755>