Date: Fri, 26 Oct 2001 16:25:09 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: John Baldwin <jhb@FreeBSD.ORG>, Poul-Henning Kamp <phk@critter.freebsd.dk>, arch@FreeBSD.ORG, Peter Wemm <peter@wemm.org>, Bakul Shah <bakul@bitblocks.com> Subject: Re: 64 bit times revisited.. Message-ID: <Pine.BSF.4.21.0110261622450.11653-100000@InterJet.elischer.org> In-Reply-To: <200110262147.f9QLlJ838887@apollo.backplane.com>
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trouble is, that ticks are: 1: not guaranteed to be constant 2/ inaccurate. also, you can represent ticks in terms of 1/(2^64) units, certainly to the accuracy of the crystals that we use for timekeeping at this time. On Fri, 26 Oct 2001, Matthew Dillon wrote: > > :> The phrase 'no freaking way' comes to mind. > :> > :> You guys are outsmarting yourselves. Seconds, ok. That's it. Nothing > :> else. The *VAST* majority of programs only need seconds, it would be > :> utterly stupid to require that they mess around with some weird fixed > :> point quantity when all they want is seconds, no matter how supposedly > :> 'simple' that messing around is (i.e. '>> 64' is not acceptable). > :> > :> -Matt > : > :Umm. Dude, this is for the kernel's internal representations. We can massage > :it in libc or in the kernel before it gets to userland. We do have to maintain > :compatibility. Slow down and think about this for a second. > : > :-- > : > :John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ > > The best kernel-internal time representnation is ticks, with a simple > baseline cache mechanism to convert it to other formats (e.g. as > required by NFS, UFS, userland, etc...). Nothing beats ticks... > a binary fixed point format doesn't even come *close* to being better > then straight ticks. > > -Matt > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-arch" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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