From owner-freebsd-hackers Mon Mar 5 12:28: 8 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from earth.backplane.com (earth-nat-cw.backplane.com [208.161.114.67]) by hub.freebsd.org (Postfix) with ESMTP id 4D53837B719 for ; Mon, 5 Mar 2001 12:28:03 -0800 (PST) (envelope-from dillon@earth.backplane.com) Received: (from dillon@localhost) by earth.backplane.com (8.11.2/8.9.3) id f25KRK442804; Mon, 5 Mar 2001 12:27:20 -0800 (PST) (envelope-from dillon) Date: Mon, 5 Mar 2001 12:27:20 -0800 (PST) From: Matt Dillon Message-Id: <200103052027.f25KRK442804@earth.backplane.com> To: Chris Dillon Cc: "E.B. Dreger" , Subject: Re: Machines are getting too damn fast References: Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :On Mon, 5 Mar 2001, E.B. Dreger wrote: : :I've got a ServerWorks III HE-SL system with 512MB of two-way :interleaved PC133 SDRAM and dual PIII-800's. Is that close enough? ::-) : :Here is my "memory bandwidth test", much much simpler and less :scientific than Matt's: : :dd if=/dev/zero of=/dev/null bs=10m count=1000 :1000+0 records in :1000+0 records out :10485760000 bytes transferred in 23.716504 secs (442129245 bytes/sec) : :I just did a recent 4.2-STABLE 'make -j 4 buildworld' on that system :in just over 34 minutes. Here's the time output: :1980.707u 768.223s 34:20.89 133.3% 1297+1456k 39517+6202io 1661pf+0w That is quite impressive for SDRAM, though I'm not exactly sure what's being measured due to the way /dev/zero and /dev/null operate. On my system the above dd test returns around 883MB/sec so I would guess that it is only doing a read-swipe on the memory. (sony 1.3G / RIMM) apollo:/home/dillon> dd if=/dev/zero of=/dev/null bs=10m count=1000 1000+0 records in 1000+0 records out 10485760000 bytes transferred in 11.867550 secs (883565697 bytes/sec) On the DELL 2400 I get: 1048576000 bytes transferred in 2.737955 secs (382977810 bytes/sec) The only thing I don't like about this baby is the IBM IDE hard drive's write performance. I only get 10-12 MBytes/sec. Read performance is incredible, though... I get 37MB/sec dd'ing from /dev/ad0s1a to /dev/null. ad0: 58644MB [119150/16/63] at ata0-master UDMA100 -Matt :> If one _truly_ needs the bandwidth of Rambus (which, IIRC, is :> higher real-world latency than SDRAM), then how about having the :> bus bandwidth to back it up? : :The higher real-world latency of RDRAM over SDRAM is what makes the :benefits of its higher bandwidth so questionable. PC2100 DDR-SDRAM -- :which has higher latencies than regular SDRAM but still lower than :RDRAM -- should have it beat soundly, though we'll have to wait for :some systems that are actually designed to take advantage of it to say :for sure. :-) : : :-- Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message