lkml.org 
[lkml]   [2006]   [May]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables
Date
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.

David
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-05-10 12:19    [W:0.100 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site