Date: Sun, 24 Feb 2002 09:50:10 -0700 (MST) From: Ronald G Minnich <rminnich@lanl.gov> To: Michael Smith <msmith@FreeBSD.ORG> Cc: "Frost, Stephen C" <stephen.c.frost@intel.com>, "'freebsd-hackers@freebsd.org'" <freebsd-hackers@FreeBSD.ORG>, "'freebsd-questions@freebsd.org'" <freebsd-questions@FreeBSD.ORG> Subject: Re: PCI Probing Utility? Message-ID: <Pine.LNX.4.33.0202240946220.27984-100000@xed.acl.lanl.gov> In-Reply-To: <200202222150.g1MLoEu02180@mass.dis.org>
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On Fri, 22 Feb 2002, Michael Smith wrote: > > > > Is there some quick, down & dirty way of assessing the bus-speeds of PCI > > slots/busses on a given box? I have a whole rack of systems with FreeBSD > > 4.5 on 'em, and need to know the PCI bus configuration for each. > > Unfortunately, no. The Yahoo! folks have worked on some old SMBios code > I wrote that might be able to extract the information you require, but > there's nothing trivially visible in PCI config space that will tell you > this. It gets worse. We just measured some Compaq SP750s here. We see a 10% variance on PCI bandwidth on boxes with the same part #s. Further looking around shows the north bridge on slow machines was fabricated in Korea, and the faster one was fabricated in Phillipines. Looking at north bridge register settings shows different values. So here are identical boxes with nothing to tell you they're different, that act different. The lesson is that if you want to know the BW of a given box, to some reasonable certainty, you will have to measure it. The boxes' sibling will give you no useful data. ron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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