Date: Tue, 25 Feb 1997 21:44:19 -0800 (PST) From: asami@vader.cs.berkeley.edu (Satoshi Asami) To: bde@zeta.org.au Cc: bde@zeta.org.au, msmith@atrad.adelaide.edu.au, freebsd-hardware@freebsd.org, ken@stox.pr.mcs.net Subject: Re: Memory speed of P6-200 (256k) Message-ID: <199702260544.VAA01458@silvia.HIP.Berkeley.EDU> In-Reply-To: <199702250918.UAA03535@godzilla.zeta.org.au> (message from Bruce Evans on Tue, 25 Feb 1997 20:18:42 %2B1100)
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I finally found what was wrong. It was pilot error (shame on me! ;). When I bought the motherboard, I went to the BIOS setup and called the menu item to reset everything to the default (like any smart boy will do). Well, the only problem was that I wasn't paying much attention and didn't notice that there were two "default"s -- the "BIOS defaults" and "setup defaults". According to the manual (that I finally read from beginning to end today), the "real" (optimized) defaults are the latter; the first one is a fail-safe, debugging-mode type of thing. Duh. So, I invoked the "setup defaults" and voila! I got >80MB/s. I even played around with the memory timings and managed to add a few MB/s. (As Chris said, changing the "RAS Precharge" from 3T to 4T helped.) Now I see something like: >> dd if=/dev/zero of=/dev/null bs=1m count=100 100+0 records in 100+0 records out 104857600 bytes transferred in 1.198974 secs (87456107 bytes/sec) There is no difference at all whether it's in ECC mode, parity mode or they are both disabled. Quite interesting. Anyway, so I'm happy now. People, thanks for all the encouragement. :) * Yes, that was the original motivation for speeding up copyout() and * copyin(). Satoshi had lots of disk bandwidth (40MB/sec?) from multiple More like >60MB/s, we had four F-W SCSI strings at one point. * controllers but couldn't use it all because copying alone was limited * to 40MB/sec. He speeded it up to 70+MB/sec on a P5-Triton system by * using the FPU, and I speeded it up a few more MB/sec by fine tuning. Yes. With the new 80MB/s copyin/out, the max throughput of reads of a ccd through the filesystem jumped from 21MB/s to 27MB/s using 4 Seagate Barracuda 15150WC's. Satoshi
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