[osg-users] Using SSE within OSG

[Gordon Tomlinson]

MS does a very poor job, 
 
I know most of our SSE is asm'ed 
 
 

  _____  

From: osg-users-bounces at lists.openscenegraph.org
[mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of David
Spilling
Sent: Tuesday, July 29, 2008 9:11 AM
To: OpenSceneGraph Users
Subject: Re: [osg-users] Using SSE within OSG


Benjamin,




may I suggest that you check the assembler code that the compilers create
when
compiling the OSG code?

 

... g++ with -march=core2 -O3 (see man page for description
of parameters) the compiler automatically uses SSE


I don't have much recent Linux/gcc experience, but can certainly attest that
the MS compilers don't do a good job of spotting SSE vectorisation
possibilities, even when you tell them to optimise with them (and this is
from reading the generated ssembler). In MS you can insert SSE intrinsics ,
which still allow the compiler to optimise the execution order and
memory/register usage e.g. based on cycle counts.

I understand (from other sources) that the Intel vectorising compilers are
much better at this, naturally.

Perhaps this is then all only aMS/Windows thing?

David




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