Date: Fri, 26 Oct 2001 23:34:13 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: John Baldwin <jhb@FreeBSD.ORG>, Bakul Shah <bakul@bitblocks.com>, Peter Wemm <peter@wemm.org>, arch@FreeBSD.ORG Subject: Re: 64 bit times revisited.. Message-ID: <8629.1004132053@critter.freebsd.dk> In-Reply-To: Your message of "Fri, 26 Oct 2001 14:28:33 PDT." <200110262128.f9QLSX838762@apollo.backplane.com>
next in thread | previous in thread | raw e-mail | index | archive | help
In message <200110262128.f9QLSX838762@apollo.backplane.com>, Matthew Dillon wri tes: > >:>::so far for the in-kernel time keeping, IMO. >:> >:> And I will also note that trying to represent both seconds and sub-seconds >:> in a single fixed point integer is a real bad idea. It makes life >:> unnecessarily difficult for the 95% of the code that only needs the >:> seconds portion. Any fractional representation should be a SEPARATE >:> field. >: >:Err it is a separate field. You have a 128-bit counter. The high 64-bits are >:the seconds portion. You just shift to get the seconds. This is not hard. >:Computers have been good at doing shift right's for quite some time now. >: >:-- >: >:John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ > > 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). [ For the record: I spent the better part of a two years on making FreeBSD the first UNIX to truly deal with nanoseconds and the first platform where NTP could work in nanoseconds, so I happen to think that I know something about this subject. I'm not going to ignore Matt on this subject until he comes to his senses or at least calms down to the point where he spends more than 3 seconds on an email before replying to it. Obviously my silence should not be interpreted to mean that I have been convinced by and agree with Matt. I maintain my recommandation on 64.64 binary timestamps as our fundamental representation. ] -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?8629.1004132053>