From: Subr Robert C Contr AFRL/HEC (Robert.Subr++at++wpafb.af.mil)
Date: 07/14/2000 06:51:41
> I am porting/developing a multi-station performer application onto a Linux
> environment. Our initial
> prototyping has been on O2s, but we are unsure whether the product
> development should target
> O2s or Linux workstations. I am looking for advice in the following
> areas:
>
> - porting problems, limitations, differences of Performer on Linux vs on
> O2
> - available configurations of acclerated Graphics cards on Linux which
> will run Performer apps
> - any comparisons in performance on the above list
> - comments on software development environments available on Linux wrt
> Performer.
> - (non-pf issue) While I have a lot of experience in Unix, and Performer,
> I have absolutely none
> in Linux. Any advice on OS level differences/gotchas would be
> appreciated as well.
>
> I am looking for either direct advice or pointers to websites or other
> resources to help me
> evaluate the feasibility, cost, impact, and selection of platform.
>
>
Daniel,
We have been "porting" several or our applications from Irix
Performer to Linux Performer since September of last year. We have tested
several types of hardware configuration.
Porting Problems-
1) Non standard tool sets provided with Irix and not Linux, we used
several applications Rapidapp a past SGI product and Rogue Wave tools which
is available for Linux but at a cost. We had to go out and find software to
replace both. For Rapidapp we are using fltk (www.fltk.org) a cross
platform open source GUI C++ development tool kit(runs under
windows,iris,linux,sun,apple.....) and moved away from Rogue Wave to STL.
It just depends on what you have in your applications. We have done some
real time testing under linux as well. The posix real time extensions do
not support the determinism that we are looking for, there is a open source
solution that can be added to the linux kernel that is very deterministic.
I do not have the web address handy right now.
2) Byte swap problems, remember the hardware architecture for Intel
is byte swapped compared to SGI mips. This becomes a factor when saving or
reading in binary data.
Hardware Comparisons-
1) The first question you need to ask yourself is what are you
trying to do with your application. We are building vis-sim applications,
at this point we do not need high color and can live with 16 bit depth
buffer (some cards will support 32 bit). You can get 32 bit color, but
getting an off the shelf card with current drivers is proving to be tough.
We have found that performance of the cards with nvidia TNT2 or Geforce
chips will easily out perform the O2 running our applications (again it
comes down to what you are doing, but I will guess that on the O2 it will be
most cases), in fact we are getting better performance in some cases than
our Octane MXEs (but they are several years old).
2) We have tested Nvidia's complete line of TNT, and Geforce cards
in our systems, We have tested Matrox 400's and E&S Lightning 1500 cards as
well as ATI rages chips. Our goal was to stay under $500 on the cards so
you will not see the high priced PC cards. Of all these I would recommend a
Geforce or Geforce2. Now all these cards do well under windows, but do to
drivers lagging and Nvidia based cards perform the best. And the
performance of the Geforce is incredible. We have had some problems with
the smp (multi-process) drivers from nvidia, they are aware and hopefully
will fix the problem, but the single processor systems just bang right in.
Now you might be asking how do the SGI Linux graphics work stations fit in,
I have not had the chance yet to run our software on one. Our office will
not buy before we try, so our SGI rep has not been able to get us one. I
will tell you that from a pure spec point of view from the briefing I have
seen, the drivers alone would make some one what to go with their package.
Currently other venders only support OpenGL 1.0 or 1.1, SGI says they
support 1.2, which if I ever get the system will most likely be a deciding
factor.
3) System speeds, I would not recommend anything slower that a 600
Mhz PIII or like. We have had very good response from both Intel and AMD.
128 MB of memory or better. I have found that application that I would need
512 meg of memory on our irix systems will run fine on 128 MB on our linux
box (there is some paging, but still works....more memory better)
Box Sets-
1) Highly recommend developing with Linux box sets. We use Redhat
and SUSE (?) and have had good luck with both. But have made mistakes of
upgrading compilers and such. This creates a supportability problems. So
develop for a box set, let the RedHat, or SUSE do the upgrades and buy the
upgraded box sets as they are released.
Well that was my two cents. In all the "porting" for our software
was not much of a port at all, it was more work getting the make files set
up than changing any code to run on linux.
Good Luck.
Rob Subr
Weapon Systems Analysis
Veridian Engineering
robert.subr++at++wpafb.af.mil
TEL: 937/255-8470
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