On Saturday 16 December 2006 12:30, M. Warner Losh wrote: > In message: <[EMAIL PROTECTED]> > > "M. L. Dodson" <[EMAIL PROTECTED]> writes: > : On a computational chemistry list I subscribe to there is a > : current thread about multi-cpu systems needing to have the cpu > : frequencies synced (this is in a Linux context). This is > : evidently not just having the cpus running at nominally the same > : frequency but something else in addition. A posting in the thread > : said variations less than 0.1% were not problematic. However, the > : poster said it was an issue in a dual cpu, dual core system he had > : set up. > : > : My questions are: > : 1. Is this real or an urban legend? > : 2. If real, is this a Linuxism or is FreeBSD affected as well? > : 3. How do you "sync" the cpus, if it is needed? > : 4. anything else some one wants to expound on along this line. > > Linux keeps the cpu's frequencies 'synchronized' so that it can use > the fast time keeping hardware (TSC). FreeBSD uses different > mechanisms for its timekeeping, so doesn't need to keep them in sync > at all, and doesn't even try at this point. Maybe this is what they > are talking about... > > Warner
That is very much in line with the context of the postings on the computational chemistry list I mentioned. This is the likely source of the issue for people on that list (very few use *BSD). They just assume if you are not using Solaris or Irix, then you must be using Linux of some flavor. And this means I don't have to bother with that particular piece of nonsense. Thanks to everyone who answered. Bud Dodson -- M. L. Dodson Email: mldodson-at-houston-dot-rr-dot-com Phone: eight_three_two-56_three-386_one _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
