[wplug] Compiler questions

Tom Rhodes trhodes at FreeBSD.org
Thu Feb 3 11:29:17 EST 2005


On Thu, 3 Feb 2005 15:06:27 +0000
Burt E Reany <breany at csc.com> wrote:


[SNIP]: Previous discussion

> 
>    There IS such an optimised compiler - but it's the proprietary compiler

Exactly what ICC is.  :)

> provided by a manufacturer for their hardware family. Proprietary and
> process control equipment that need such intense thruput, either due to
> load factors or marketing requirements, are therefore both restrictive and
> expensive. Open source systems don't pretend to wring such intensive use
> out of every hardware platform, but provide consistancy across hardware
> boundaries, and support migration between hardware families.

My concern is better binary output.  Over at FreeBSD, a couple of
us have been researching the benefits of supporting both ICC and
GCC, as well as other compilers.

Our tests have proven that ICC produces better code on Intel
platforms, as we expected; however, there are reservations:

1: We have only tested the kernel on P4, and P3 chips, nothing
   has been tested with Celerons or on AMD chips.  We assume
   that since it's an i386 compatible CPU, we should get some
   performance increase; however, our committer who works at AMD
   has not released anything more than "I expect it to produce
   better binaries ..."

2: Binaries produced by ICC can only be released by the "FreeBSD
   Project" entity.  Due to license restrictions, I personally
   cannot release code compiled using ICC unless it's released
   officially by the project at large.

3: Code duplication/code issues.  ICC doesn't seem to like ASM,
   but I am only playing a parrot here.  Something was mentioned
   about BIG ENDIAN and LITTLE ENDIAN support, but we could ifdef
   around that, I think.

>    In addition, the unavailability of source code for proprietary systems
> posts a disadvantage to the application developers in that environment that
> open source developers don't suffer from.

I've only had one instance where a proprietary company would not
even release documentation to me.  Granted, my count of trying to
obtain docs and specifications is a low number of 5.

-- 
Tom Rhodes


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