Date: Thu, 2 Sep 1999 13:44:28 -0700 (PDT) From: Julian Elischer <julian@whistle.com> To: Nate Williams <nate@mt.sri.com> Cc: nsayer@FreeBSD.ORG, freebsd-hackers@FreeBSD.ORG Subject: Re: CFD: "bogomips" CPU performance metric Message-ID: <Pine.BSF.3.95.990902134236.3714F-100000@current1.whistle.com> In-Reply-To: <199909022027.OAA28124@mt.sri.com>
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It was there... when I added the code to calibrate the delay loops originally and added the DELAY macro, it printed out the callibration factor.. (DELAY was originally a spin loop) It wasn't called 'BOGOMIPS...' On Thu, 2 Sep 1999, Nate Williams wrote: > > There was such a thing in 386BSD and FreeBSD1.0 > > I remember no such thing doing a 'bogomips' to compare against Linux. > Certainly not in 386BSD. > > > > Nate > > > > > I certainly thing it was a worth-while thing. > > I'd try make the loop as similar to the Linux one so that they are > > comparable. > > > > On Thu, 2 Sep 1999, Nick Sayer wrote: > > > > > Linux generates a meric of CPU performance as a byproduct of calibrating > > > a delay loop. > > > We don't require doing any such thing, and so adding it would be purely > > > cosmetic. > > > However, I allege that cosmetic things aren't in and of themselves evil, > > > so long as > > > they don't break anything in the process. > > > > > > I would like to generate a number that will hopefully be reasonably > > > compatible with > > > the one Linux spits out. The best method I have come up with is to have > > > a similar > > > (the same?) count down loop in assembler. Have it count down from > > > 1,000,000 and > > > see how much nanotime() has gone by. NANSPERSEC/nansused = bogomips. > > > A 1 bogomips machine will take an extra second to do this (anything > > > likely to be > > > even able to run FreeBSD should exceed 1 BM - yes, ha ha), and a kBM CPU > > > > > > can do it in 1 ms. Perhaps in the future a prescaler might be required, > > > but > > > this whole thing is just really chrome anyway. > > > > > > Would anyone scream and projectile-vomit if I added this to identcpu.c? > > > > > > > > > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > with "unsubscribe freebsd-hackers" in the body of the message > > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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