From owner-freebsd-hackers Mon Mar 5 15:25:18 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 1221C37B718 for ; Mon, 5 Mar 2001 15:25:16 -0800 (PST) (envelope-from dillon@earth.backplane.com) Received: (from dillon@localhost) by earth.backplane.com (8.11.2/8.9.3) id f25NOin45226; Mon, 5 Mar 2001 15:24:44 -0800 (PST) (envelope-from dillon) Date: Mon, 5 Mar 2001 15:24:44 -0800 (PST) From: Matt Dillon Message-Id: <200103052324.f25NOin45226@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 :throughput. For example, on the PIII-850 (116MHz FSB and SDRAM, its :overclocked) here on my desk with 256KB L2 cache: : :dd if=/dev/zero of=/dev/null bs=512k count=4000 :4000+0 records in :4000+0 records out :2097152000 bytes transferred in 8.229456 secs (254834825 bytes/sec) : :dd if=/dev/zero of=/dev/null bs=128k count=16000 :16000+0 records in :16000+0 records out :2097152000 bytes transferred in 1.204001 secs (1741819224 bytes/sec) : :Now THAT is a significant difference. :-) Interesting. I get very different results with the 1.3 GHz P4. The best I seem to get is 1.4 GBytes/sec. I'm not sure what the L2 cache is on the box, but it's definitely a consumer model. dd if=/dev/zero of=/dev/null bs=512k count=4000 2097152000 bytes transferred in 2.363903 secs (887156520 bytes/sec) dd if=/dev/zero of=/dev/null bs=128k count=16000 2097152000 bytes transferred in 1.471046 secs (1425619621 bytes/sec) If I use lower block sizes the syscall overhead blows up the performance (it gets lower rather then higher). So I figure I don't have as much L2 as on your system. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message