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From: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Message-Id: <199603082252.XAA13934@labinfo.iet.unipi.it>
Subject: IDE performance
To: hackers@freebsd.org
Date: Fri, 8 Mar 1996 23:52:22 +0100 (MET)
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Can someone tell me why my IDE disk (WDC AC31600, 1.6GB) mounted
on the primary IDE (together with a slave ATAPI CDROM) runs at
5.5MB/s (both with iozone 128 8192 and with bonnie, block transfer),
and the same disk on the secondary IDE does "just" little more than
3.1MB/s ?

This is on a Pentium100, Intel Zappa MB with built-in IDE controller,
32MB ram, 2.1R. The wdc driver is compiled with flags 0x80ff80ff on
both primary and secondary interfaces.

Is this a feature of the motherboard, or something in the kernel ?
(or just because IDE sucks... :)

BTW, I'd like to try the ccd driver on multiple IDE disks [at 5.5MB
each, I am really curious how they scale up!]. Any idea if I can
boot/swap on a ccd "unit" ? And, in this case, any idea on how can
I install the system on a ccd "unit" ?

Alternatively, I can boot a diskless kernel but at leas having local
swap would be nice.

	Luigi
====================================================================
Luigi Rizzo                     Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it       Universita' di Pisa
tel: +39-50-568533              via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522              http://www.iet.unipi.it/~luigi/
====================================================================