Messages in this thread | | | Date | Mon, 21 Jan 2013 22:49:00 +0000 | From | Russell King - ARM Linux <> | Subject | Re: One of these things (CONFIG_HZ) is not like the others.. |
| |
On Mon, Jan 21, 2013 at 02:36:13PM -0800, John Stultz wrote: > Well, Russell brought up a case that doesn't handle this. If a system > *can't* do HZ=100, but can do HZ=200. > > Though there are hacks, of course, that might get around this (skip > every other interrupt at 200HZ).
Note: in the early days of EBSA110 support, yes, we did that, so that we could have HZ=100 everywhere. _However_ it sufficiently peturbed NTP that it basically was unable to slew the clock in any sane manner. I never got to the bottom of why that was, and when USER_HZ was decoupled from the kernel HZ, it allowed the problem to be fixed, and the kernel code to become a _lot_ cleaner.
| |