>> That's from 2008. >> Was there anything in there that you thought was particularly interesting or >> surprising?
> The actual numbers. I've seen the logic before. That was a long time ago. Any numbers are likely to be misleading. Best to collect your own. How about "Trust, but verify." PC have two crystals, one for the CPU and one for the RTC/TOY clock. In the old days of that paper, Linux used an interrupt from the RTC clock for timekeeping. The TSC was used to interpolate between ticks but the main timekeeping use the RTC crystal. Current Linux timekeeping uses the TSC which is derived from the CPU crystal. The RTC crystal probably has a much better temp coefficient than the CPU crystal and/or it is probably farther from the CPU so gets less temperature change under load. There is another worm in this can. On most PCs, the CPU clock is "spread" to dance under the FCC EMI rules. I don't have any data on the temperature coefficient of that stuff. (SoC boards like the Raspberry Pi typically don't do that.) They used 100 megabit ethernet. Anything more advanced than a Raspberry Pi has gigabit these days. -- These are my opinions. I hate spam. _______________________________________________ devel mailing list devel@ntpsec.org http://lists.ntpsec.org/mailman/listinfo/devel
