On Mon, Nov 12, 2012 at 09:41:22AM +0100, Florian Weimer wrote:
> On 11/10/2012 05:26 PM, Ville Skyttä wrote:
> >On 2012-11-09 18:27, Matthew Miller wrote:
> >>The js package is 6.5MB.
> >
> >BTW I suppose that could be significantly reduced by linking /usr/bin/js
> >with the dynamic libmozjs instead of the static one generated during the
> >build. It seems to take something more than just the attached patch though.
>
> Most interpreters deliberately do this because non-PIC code is
> significantly faster than PIC code, especially on architectures
> without IP-relative addressing.
>
Two notes: tis might be the default case upstream but it's not normal
behaviour in what we package for Fedora:
$ ldd `which perl`|grep libperl
libperl.so => /usr/lib64/perl5/CORE/libperl.so (0x00000034d1e00000)
$ ldd `which python`|grep libpython
libpython2.7.so.1.0 => /lib64/libpython2.7.so.1.0 (0x00000034da000000)
$ ldd `which ruby`|grep libruby
libruby.so.1.9 => /lib64/libruby.so.1.9 (0x00000034bca00000)
ajax (IIRC) analyzed the speed increase of non-PIC code when he worked on
this:
https://fedoraproject.org/wiki/User:Tibbs/Text_Relocation_Guidelines?rd=User:Tibbs/Static_Library_PICness_Guidelines#Rationale
He found a "small performance benefit", not "significantly faster"
performance. He also made the case that non-PIC code has negative
performance characteristics that are weighed against the gains.
-Toshio
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