lkml.org 
[lkml]   [2002]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] 2.5.21 Nonlinear CPU support
Date
In message <3D05A9E8.FF0DA223@zip.com.au> you write:
> and slowdown:

ARGH! STOP IT! I realize it's 'leet to be continually worrying about
possible microoptimizations, but I challenge you to *measure* the
slowdown between:

> > - for (i = 0; i < smp_num_cpus; i++) {
> > - int logical = cpu_logical_map(i);

and

> > + for (i = 0; i < NR_CPUS; i++) {
> > + if (!cpu_online(i))
> > + continue;

*Especially* in this context. Sure, a new "max_cpu_number" or
"cpu_for_each(i)" macro would fix this, but at the expense of using up
additional stack in the reader's brain.

Let's not perpetuate the myth that everything in the kernel needs to
be tuned to the last cycle at all costs, hm?

Yes, you stepped on a sore point 8)
Rusty.
PS. Of course, you know the correct answer, anyway.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
-
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 13:26    [W:0.137 / U:10.848 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site