RE: [PATCH] i386: Selectable Frequency of the Timer Interrupt

Brown, Len
2005-07-15T16:35:54Z

>That's an APIC bug.
>When Intel originally released the APIC (some
>thirteen years ago) they stated it should be used as a source of the
timer
>interrupt instead of the 8254. There is no excuse for changing the
>behaviour after so many years. So if you are on a broken system, you
may
>want to work around the bug, but it shouldn't impact good systems.

I'm perfectly happy having Linux optimize itself for the hardware
that it is running on. However, the (harsh, I know) reality is that
systems with a reliable LAPIC timer in the face of C3 do not exist
today, and probably never will. (don't shoot me, it wasn't my design
decision, I'm just the messenger:-) Further, I expect that power saving
features, such as C3, will become more important and deployed more
widely in the future, rather than less widely.

So, the 13-year-old design advice will continue to apply to
13-year-old systems, but newer systems with C3 and HPET
should be using them.

-Len