[PVFS-developers] Re: libpvfs

[Porter Don]

Here is a thread entry from the debian mailing list that I found which goes
over this issue.  If we believe with the author of this note, he claims a
~5% performance hit for needlessly using PIC and generally advises against
it.

http://lists.debian.org/debian-mentors/2002/debian-mentors-200203/msg00172.h
tml

In general, I would rather take a little longer for compilation (which
doesn't take very long on a newer box) than have my applications run slower
- speed is, after all, a primary appeal of pvfs.

-----Original Message-----
From: Nathan Poznick
To: 'pvfs-developers@www.beowulf-underground.org'
Sent: 1/9/04 9:32 AM
Subject: Re: [PVFS-developers] Re: libpvfs

Thus spake Robert Latham:
> About all i know aobut -fPIC is that it's something Debian requires of
> all libraries :>  Just what *is* the performance penalty of making a
> library posistion independent?  

Specifically, they require that all shared libraries be built with
-fPIC, and all static libraries be built without it.  So there's a
build-time penalty because you have to compile everything twice :)

I have no answer on the runtime penalty.  When it comes down to it,
that's all CPU register voodoo to me.

-- 
Nathan Poznick <poznick@conwaycorp.net>

He that falls in love with himself will have no rivals. - Benjamin
Franklin