Date: Thu, 2 Sep 1999 14:27:24 -0600 From: Nate Williams <nate@mt.sri.com> To: Julian Elischer <julian@whistle.com> Cc: nsayer@FreeBSD.ORG, freebsd-hackers@FreeBSD.ORG Subject: Re: CFD: "bogomips" CPU performance metric Message-ID: <199909022027.OAA28124@mt.sri.com> In-Reply-To: <Pine.BSF.3.95.990902111506.3714C-100000@current1.whistle.com> References: <37CEB68D.848BDAF8@sftw.com> <Pine.BSF.3.95.990902111506.3714C-100000@current1.whistle.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> 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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199909022027.OAA28124>