Date: Sat, 07 Oct 1995 17:22:10 -0700 From: "Justin T. Gibbs" <gibbs@freefall.FreeBSD.org> To: se@ZPR.Uni-Koeln.DE (Stefan Esser) Cc: "Kenneth D. Merry" <ken@rflab1.gtri.gatech.edu>, hackers@freebsd.org Subject: Re: VLB Disk Controllers Message-ID: <199510080022.RAA26728@aslan.cdrom.com> In-Reply-To: Your message of "Sun, 08 Oct 1995 00:35:34 BST." <199510072335.AA14520@Sysiphos>
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>On Oct 7, 19:13, "Kenneth D. Merry" wrote: >} Subject: Re: VLB Disk Controllers > >} Adaptec 2842 on a i486DX4/100 VLB (QUANTUM XP34300) (Atlas, fast disk) >} output for disklatency /dev/rsd0: >} Command overhead is 567 usec (time_4096 = 1002, time_8192 = 1438) >} transfer speed is 9.40748e+06 bytes/sec > >Well, you beat me, though not by much :) The important thing is that we have support for enough controllers in FreeBSD that we can actually bicker about which is faster. :) >Something I just noticed is the big difference >in results I get using /dev/rsd0 vs. /dev/rsd0a: > ># disklatency /dev/rsd0 >Command overhead is 719 usec (time_4096 = 1198, time_8192 = 1677) >transfer speed is 8.55617e+06 bytes/sec > ># disklatency /dev/rsd0a >Command overhead is 807 usec (time_4096 = 1272, time_8192 = 1738) >transfer speed is 8.80588e+06 bytes/sec > >Any ideas ??? Slice code? It may be that we take some steps to validate the disklable for that partition, do additional range checks etc. Bruce probably knows. >STefan > >-- > Stefan Esser, Zentrum fuer Paralleles Rechnen Tel: +49 221 4706021 > Universitaet zu Koeln, Weyertal 80, 50931 Koeln FAX: +49 221 4705160 > ============================================================================= >= > http://www.zpr.uni-koeln.de/staff/esser/esser.html <se@ZPR.Uni-Koeln.DE> -- Justin T. Gibbs =========================================== Software Developer - Walnut Creek CDROM FreeBSD: Turning PCs into workstations ===========================================
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