This is the mail archive of the mailing list for the binutils project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]


On 18/12/14 07:11, Alan Modra wrote:
On Thu, Dec 18, 2014 at 10:26:03AM +1100, Chris Johns wrote:
>On 17/12/2014 12:34 pm, Richard Henderson wrote:
> >It seems to me that most powerpc hardware these days is server based,  and very
> >little remains at the desktop class.

There are not only servers and desktops in the world. We have also embedded devices.

>What about embedded devices with as Freescale's QorIQ T2080 and T4240 ?
> >And in the server environment, IBM has
> >been recommending a 64k page size.
>Would this change effect RTEMS and it devices ?
Yes, it would.  However, the effect isn't huge one way or another.

Richard quoting IBM's recommendation of a 64k page size really hasn't
anything to do with COMMONPAGESIZE, or at least not as much as you
might think..  You can quite happily run a binary linked with
COMMONPAGESIZE set to 4k on a system using 64k pages.  COMMONPAGESIZE
or -z common-page-size is really about where the linker starts the
data segment, following on from the text segment.  It boils down to
a trade-off between memory pages and disk pages, and the net result of
increasing COMMONPAGESIZE to 64k for a system running with 4k pages
is that you'll tend to have bigger on-disk binaries but won't use any
more memory than with the "proper" 4k COMMONPAGESIZE.  On the other
hand if you really are running with 64k pages, there will be binaries
where you could save a 64k page of memory if you'd specified the
proper COMMONPAGESIZE at link time.

Overall, I think the increased COMMONPAGESIZE is beneficial, so I'm
happy with the patch.

Since RTEMS uses its own linker command files, this change has no impact on RTEMS. Otherwise it would be a problem since some chips have about 64KiB of RAM.

Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  :
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]