Messages in this thread | | | Date | Tue, 4 Oct 2005 07:51:11 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] ktimers subsystem 2.6.14-rc2-kt5 |
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* George Anzinger <george@mvista.com> wrote:
> > yeah, and that's an assumption that simplifies things on SMP > > significantly. PIT on SMP systems for HRT is so gross that it's not > > funny. If anyone wants to revive that notion, please do a separate > > patch and make the case convincing enough ... > > Lets not talk about PIT, but, a lot of SMP platforms do NOT have per > cpu timers. For those, it would seem having per cpu lists to handle > the timer is not really reasonable.
frankly, such systems are rare, and are an afterthought at most. Think about it: 8 CPUs and only one hres timer source? It cannot work nor scale well.
i agree that they might eventually be handled (although i think we shouldnt bother, all sane SMP designs have per-CPU timers), but we definite wont design for them. What such an architecture has to do is to provide the proper do_hr_timer_int() and arch_hrtimer_reprogram() semantics, via locking around that timer source (naturally), and via cross-CPU calls - as if they were per-CPU timers.
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