From mboxrd@z Thu Jan 1 00:00:00 1970 In-Reply-To: <199901060601.RAA00588@tango.anu.edu.au> Date: Wed, 6 Jan 1999 17:02:22 +0100 To: tas@mindspring.com, linuxppc-dev@lists.linuxppc.org, Paul.Mackerras@cs.anu.edu.au From: Benjamin Herrenschmidt Subject: Great IDE perf (WAS: Strange PMAC IDE performance) Message-Id: <19990106170222.030778@mail.mipsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Wed, Jan 6, 1999, Paul Mackerras wrote: >I found a register at 0xf3020200 on my powermac G3 which affects the >speed of disk transfers. This is at offset 0x200 from the base >address of the IDE interface and it is a 32-bit little-endian >register. After booting Linux, it has 0x2f8526 in it, but under MacOS >it has 0x211025. Putting 0x211025 in (with xmon) increased the speed >reported by hdparm -tT /dev/hda from 1.89MB/s to 9.7MB/s ! The disk >is a WDC 24300ACL (as reported by hdparm -i /dev/hda). The other >hdparm settings were -d1 -u1 -m16. I tried the manipulation with xmon on my wallstreet PowerBook, using today's vger 2.2-pre4 and hdparam test jumped from 1.88Mb/s to 6.3MB/s !!! (At first, I forgot to flush the caches, so I got 50Mb/s ;-) Also, the register is replicated all the way from +0x200 to +0x3FF so it looks like it's really a single register sitting there. That's great ! -- E-Mail: BenH. Web : [[ This message was sent via the linuxppc-dev mailing list. Replies are ]] [[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]] [[ reply is of general interest. To unsubscribe from linuxppc-dev, send ]] [[ the message 'unsubscribe' to linuxppc-dev-request@lists.linuxppc.org ]]