Messages in this thread | | | From | David Howells <> | Subject | Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables | Date | Wed, 10 May 2006 11:14:53 +0100 |
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Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> > That first cache line of current_thread_info() should be so hot that > > it's probably just fine to use current_thread_info()->task since > > you're just doing a mask on a fixed register (r1) to implement that. > > Iirc, he tried that, though it did bloat the kernel size a bit due the > the amount of occurences of current-> in there. We are now thinking > about either dedicating a register to current (that would avoid the > problem of printk() using it in start_kernel before we get the per-cpu > areas setup) in addition to __thread (heh, we have lots of registers on > ppc :) or maybe putting current back in the paca...
I dedicated registers to current and current threadinfo in the FRV arch. As I recall doing that improved both performance and code size quite a bit. It also means that I get sensible bug panic reports when the stack pointer overruns the stack space.
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