Messages in this thread | | | Date | Fri, 11 Apr 2008 09:55:54 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: set_cyc2ns_scale() remove tsc_now and ns_now |
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* Andi Kleen <andi@firstfloor.org> wrote:
> (actually it is still the wrong time -- really needs a grace period > during which the TSC is not used > ftp://firstfloor.org/pub/ak/quilt/patches/sched-clock implemented some > of these ideas against an older kernel)
recent CPUs have constant-freq TSCs so it's mostly a legacy issue, but the affected installed base is still significant to warrant a fix.
we dont really have to worry about complications like grace periods - higher layers in the scheduler protect against temporary sched_clock() outliers. So i think this can all be done much simpler. Just get rid of the global cpu_khz notion, sched_clock() should simply follow the ->freq value - and that's it.
Ingo
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