lkml.org 
[lkml]   [2002]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] I3 sched tweaks...
Ingo Molnar writes:

> It's
> slightly cheaper to pass an already existing (calculated) 'current'
> pointer over to another function, instead of calculating it once more in
> that function.

On x86 that's true; many other architectures - alpha, ia64, m68k,
mips, mips64, parisc, ppc, ppc64, sparc, sparc64 - keep current in a
register already and thus it is slightly more expensive to pass it as
a parameter instead of just using current in the function.

Either way surely the cost is tiny, and the maintainability
considerations should prevail. Having a function which takes a
task_struct * parameter which _has_ to be current sounds to me like an
invitation for somebody to get it wrong down the track.

Paul.
-
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: 2005-03-22 13:23    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site