Re: [PATCH] x86: set_cyc2ns_scale() remove tsc_now and ns_now

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From: Andi Kleen
Date: Friday, April 11, 2008 - 12:42 am

Karsten Wiese <fzu@wemgehoertderstaat.de> writes:


I don't think you should remove those. At some point the offset
needs to be reset when the frequency scale changes for obvious reasons, 
and that needs to be fixed, not the code removed. Right now you'll get
scheduling inconsistencies during frequency changes on 
!constant_tsc CPUs.

(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)

-Andi

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Messages in current thread:
[PATCH] x86: set_cyc2ns_scale() remove tsc_now and ns_now, Karsten Wiese, (Thu Apr 10, 2:31 pm)
Re: [PATCH] x86: set_cyc2ns_scale() remove tsc_now and ns_now, Andi Kleen, (Fri Apr 11, 12:42 am)
Re: [PATCH] x86: set_cyc2ns_scale() remove tsc_now and ns_now, Guillaume Chazarain, (Fri Apr 11, 1:25 am)