lkml.org 
[lkml]   [2007]   [Jun]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: -Os versus -O2
On Sun, Jun 24, 2007 at 09:34:05PM -0400, Jeff Garzik wrote:
> Adrian Bunk wrote:
>> The interesting questions are:
>> Does -Os still sometimes generate faster code with gcc 4.2?
>> If yes, why?
>
> Smaller code can mean fewer page faults, fewer cache invalidations, etc.
>
> It's not just a matter of compiler code generation, gotta look at the whole
> picture.

Sure, but my point is that if the kernel is considered special and the
best optimization for the kernel is therefore between -Os and -O2, we
should try to find this point of best optimization.

This should address Arjans point that -Os might not be best choice for
best performance (and it's actually our fault if gcc generates stupid
but small code when we use -Os).

> Jeff

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

-
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: 2007-06-25 03:49    [W:1.496 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site