Re: [PATCH] Start of compat32.h (again)

Jakub Jelinek (jakub@redhat.com)
Mon, 2 Dec 2002 04:36:45 -0500


On Mon, Dec 02, 2002 at 10:07:56AM +0100, Andi Kleen wrote:
> > The data is where I'd say the bloat would be, and lo and behold is a
> > nearly 7-fold increase for the sample you give us _only_ in the .data
> > section.
>
> .data is normally not a significant part of programs, because few programs
> use global variables that heavily (yes, there are exceptions, like that emacs
> thing, but it's not common)

.data is significant, that is e.g. something that cannot be shared
between processes.
The fastest model on x86-64 would IMHO be a 32-bit model using all
registers, rip relative addressing and register passing conventions
(ie. a 3rd ABI).

> > BTW, I bet your dynamic relocation tables are a bit larger too.
>
> Somewhat, but does it matter? They are not kept in memory anyways.

Surely it does, for startup time (unless prelinking) the 3 times bigger .rel*
sections mean significantly more data needs to be loaded into RAM and
caches, for short-lived processes it matters a lot.

Jakub
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