Re: 'global' rq->clock

From: David Miller
Date: Fri May 02 2008 - 17:48:38 EST


From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Date: Fri, 02 May 2008 21:56:26 +0200

> Ok, the the below would need something that relates tick_timestamp's to
> one another.. probably sucks without it..
>
> OTOH, Andi said he was working on a fastish global sched_clock() thingy,
> Andi got a link to that code?

While I'm fine with this kind of stuff being added to constantly cope
with x86's joke of a TSC register implementation, it's starting to
become an enormous burdon for platforms where the TICK source actually
works properly.

Heck, on my Niagara2 chips, all 64 cpus use the same physical register
for the TICK source, it physically can't get desynchronized :-)

So, a way to turn all of this muck off would be much appreciated.
I'm happy to test anything on sparc64, and I'm sure the powerpc
folks are as well.

And I also heard a rumor that Peter has access to a machine with a
stable tick source for testing :-)
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