Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [patch 2.6.16-rc5-mm2] sched_cleanup-V17 - task throttling patch 1 of 2 | Date | Sat, 4 Mar 2006 17:50:20 +1100 |
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On Saturday 04 March 2006 17:50, Mike Galbraith wrote: > On Sat, 2006-03-04 at 16:54 +1100, Con Kolivas wrote: > > On Saturday 04 March 2006 16:40, Randy.Dunlap wrote: > > > On Sat, 04 Mar 2006 06:29:47 +0100 Mike Galbraith wrote: > > > > On Sat, 2006-03-04 at 16:24 +1100, Con Kolivas wrote: > > > > > On Saturday 04 March 2006 16:20, Mike Galbraith wrote: > > > > > > On Sat, 2006-03-04 at 13:33 +1100, Peter Williams wrote: > > > > > > > > include/linux/sched.h | 3 - > > > > > > > > kernel/sched.c | 136 > > > > > > > > +++++++++++++++++++++++++++++--------------------- 2 files > > > > > > > > changed, 82 insertions(+), 57 deletions(-) > > > > > > > > > > > > > > > > --- linux-2.6.16-rc5-mm2/include/linux/sched.h.org 2006-03-01 > > > > > > > > 15:06:22.000000000 +0100 +++ > > > > > > > > linux-2.6.16-rc5-mm2/include/linux/sched.h 2006-03-02 > > > > > > > > 08:33:12.000000000 +0100 @@ -720,7 +720,8 @@ > > > > > > > > > > > > > > > > unsigned long policy; > > > > > > > > cpumask_t cpus_allowed; > > > > > > > > - unsigned int time_slice, first_time_slice; > > > > > > > > + int time_slice; > > > > > > > > > > > > > > Can you guarantee that int is big enough to hold a time slice > > > > > > > in nanoseconds on all systems? I think that you'll need more > > > > > > > than 16 bits. > > > > > > > > > > > > Nope, that's a big fat bug. > > > > > > > > > > Most ints are 32bit anyway, but even a 32 bit unsigned int > > > > > overflows with nanoseconds at 4.2 seconds. A signed one at about > > > > > half that. Our timeslices are never that large, but then int isn't > > > > > always 32bit either. > > > > > > > > Yup. I just didn't realize that there were 16 bit integers out > > > > there. > > > > > > LDD 3rd ed. doesn't know about them either. Same for me. > > > > Alright I made that up, but it might not be one day :P > > Well Fudgecicles. Now you guys have gotten me aaaaall confused. Are > there cpus out there (in generic linux land) that have 16 bit integers > or not? 16 bit integers existing in a 32 bit cpu OS seems like an alien > concept to me, but I'm not a twisted cpu designer... I'll just go with > the flow ;-)
All supported architectures on linux currently use 32bits for int. That should give you 2.1 seconds in nanoseconds. Sorry my legacy of remembering when ints were 8 bits coloured me.
Cheers, Con - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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