Messages in this thread | | | Date | Fri, 28 Jul 2000 16:34:25 +0200 | From | Jamie Lokier <> | Subject | Re: sysconf (was Re: RLIM_INFINITY inconsistency between archs) |
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Andi Kleen wrote: > H. Peter Anvin wrote: > > I don't think we want to do this! IMO, HZ should not get exported to > > user space *AT ALL*. Instead, for the few interfaces that need it, > > we'll export a "user space HZ" (USER_HZ) which is fixed. No need for > > a kernel hack. When we support nonstandard values for HZ, we need to > > fix the few interfaces that actually export jiffies values to convert > > from "user jiffies" to real jiffies. > > I think the point is less HZ as unit (it shouldn't be a user visible one), > but some programs want to know the timer tick to adapt themselves to it; e.g. > to calibrate their timers. Of course it is only an approximation because > timer events can always be late in a multitasking environment, but it > usually should work out.
Indeed, such as:
1. select() up until desired time minus 1 tick. 2. busy wait using gettimeofday().
I had to do that to get a simple X snake game to appear smooth on Solaris. Though I never did ask Solaris for the HZ value, I just used a value that seemed to work well. In this case a self-calibrating method would probably be ok -- if you're missing deadlines regularly, increase estimate of tick time.
-- Jamie
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