Date: Sun, 5 Dec 1999 16:05:59 -0500 (EST) From: Andrew Gallatin <gallatin@cs.duke.edu> To: obrien@NUXI.com Cc: freebsd-alpha@FreeBSD.ORG Subject: Re: 64bitPCI Message-ID: <14410.53049.351748.935865@grasshopper.cs.duke.edu> In-Reply-To: <19991205124526.I34918@dragon.nuxi.com> References: <19991205195643.A43682@chuggalug.clues.com> <14410.50100.810277.209073@grasshopper.cs.duke.edu> <19991205124526.I34918@dragon.nuxi.com>
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David O'Brien writes: > On Sun, Dec 05, 1999 at 03:07:15PM -0500, Andrew Gallatin wrote: > > > I am building test platforms for an application with very great disk and > > > Network IO requirements. Which of the FreeBSD supported alphas have a > > > 64bit PCI bus ? > > > > Yes. You want something based on the tsunami chipset found in the > > My PC164SX has two 64-bit PCI slots. How good is the 64-bit > implementation on this board? > Not so good. It has the pyxis chipset & doesn't have good memory bandwidth. (as to "good" I'm talking better than 300MB/sec for the xp1000 and better than 500MB/sec for the ds20 using the Hbench bw_mem_cp: $Id: bw_mem_cp.c,v 1.7 1997/06/27 00:33:58 abrown Exp $) I'm not sure what the 164sx's memory bandwidth is, but I suspect that it is < 120MB/sec for the hbench copy test. There are 64-bit DMA benchmarks online at http://www.myri.com:80/scs/PCI64X/performance (Read E2L as DMA-read and L2E as DMA-write.) They are a little out of date & rather misleading, since they do not indicate if the machine can perform like that with any sort of competing memory system load from the CPU. Like copyin/copyout. The reason why I mentioned our 1147Mb/sec TCP/IP number from the XP1000 was that both machines were copying AND DMA'ing at better than 140MB/sec. That was with the normal FreeBSD TCP/IP stack, the only modification being that we were using a 6 line patch to enable hardware checksum offloading on the receiver.. Cheers, Drew ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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