rec.autos.simulators

As a bit of an experiment, I have just installed GPL on a Win2K
Professional machine.  The machine has a Voodoo3 3000 card, and an SBLive
sound card.

The installation works just fine, and seems little different to Win98.

My question is this - has anybody tried this sort of configuration on a
twin processor machine?  The Voodoo drivers mention a single processor,
but do they work on a multiprocessor box too?  If so, what sort of
performance does the second processor give to the overall FPS?

Cheers,

Steve.

 - George

Not exactly true.  Even a single threaded application will
run on both processors (it just won't run on both at once)
so neither processor sits there idle while the other spins
away.  Multi-threaded applications such as GPL can run on
multiple processors at the same time, the problem in GPL
is that the other threads aren't really doing enough for
one to notice the benefits of SMP.

So you can run a server and race at the same time, other
than that there isn't much to be gained.

 - George

Jason.

In Win98 I noticed an 8-10fps improvement with a V3 over a TNT, so I
suspect if V3 drivers come out for Win2k that work with GPL, that we
can expect a similar improvement in Win2k.  36fps from race start to
finish would then be a reality.

BTW, GPL as of ver 1.1 was written to support dual-proc systems (but
not 4, 8 or 16 processors ;).  This from Randy Cassidy himself.

Bill.

On Mon, 13 Mar 2000 17:32 +0000 (GMT Standard Time),

second one just sits there.<<

This isn't true at all, unless you are refering to having a
multi-threaded app.  As far as I am aware (and I'm a software developer),
there are no Win32 APIs that allow you pick and choose which processor
your code runs on.  If you have a multi-threaded application, then the
Operating System will load balance them across the processors.

However, even a single threaded app will benefit from multi-processors
because the OS uses CPU cycles with the stuff that it has running, so if
nothing else that load is balanced across the processors (not that it
would necessarily show a big difference).

I'm guessing that the Voodoo3 Win2K drivers rely on some sort of timing
that gets messed up when there are two processors - does anybody know
whether they are planning a multi-processor version?  (I think I'll go ask
in a 3DFX newsgroup, and report back).

The current state of play is that for 300UKP, you could get two Celerons
running at 533, and put them in an ABit BP6 dual motherboard, and this
gives you quite a lot of power for your money.  In addition this, when not
*** a dual processor box gives a far more responsive feel than a single
(and even faster) processor machine.

It's got to be the future...

Steve.

No, not George.  "Jeff Murchison JR" wrote what you quoted.
Please be more careful in the future.

Feel free to look up:

SetThreadAffinityMask/SetProcessorAffinityMask

in MSDN.

I believe Q3 & Q3A run under SMP on 3dfx hardware.  Could
be wrong though since I don't play either of these games.
Regardless the difficulty is in rendering from more than a
single thread (as in Quake) , not rendering from a single
thread in a mult-threaded application (like GPL).

Be sure to don your protective gear, their newsgroups are
rather harsh towards those who want to do something other
than speculate and slag.

 - George

You can set processor affinity on each thread. It's a hint only, and Windows
might choose to not honor it.

I confirmed for myself last night that the V3 driver doesn't work on a dual
processor machine. Don't even try it; you won't get to the options screen
after doing this. I was thinking of removing Win98 from the system after the
system stabilizes, but it looks like I might keep it around just for
emergency software repairs, such as these.

The TNT2 goes back in later this evening, and I'll see how things run with
both processors going. The MSFF wheel is working fine business, and if frame
rates viewing replays in NT are any indication, things should be very happy
here. I really wish I had the sense to buy a PCI V3, instead of competing
with the TNT2 for the AGP slot... Oh well, there's always E-Bay. :-) I still
think it's awful that the NT V3 drivers worked with dual processors, but not
the new one for W2K.

Michael.

Very likely, it's a race condition that can only occur with true
multi-processing. I'm sure they're working on it... the question really is
when, not if.

I also downloaded the Q3A demo and it works just fine.  So I dispute
your confirmation.

 - George

scooter

I'll give it another try... where's that video mode switch setting?

Michael.

- George

Yes, sorry, my fault completely - I should have been paying more
attention.

You live and learn, don't you?  I don't suppose I've ever needed to use
them, however, I did find this:

"Setting thread affinity should generally be avoided, because it can
interfere with the scheduler's ability to schedule threads effectively
across processors. This can decrease the performance gains produced by
parallel processing. An appropriate use of thread affinity is testing each
processor."

So it is interesting as to why anybody would want to use them under
normal circumstances.

If SMP boxes become more popular, then it would be interesting to see how
sims could really harness their power by putting AI driver calculations on
multiple threads.  I wonder what GPL uses its threads for.

Cheers,

Steve.

(which I wrote for a completely different issue years ago).
I'll send it to you if you like since the versions floating
around the Internet GPL sites are rather stale.<<

So, are you saying that if you fix GPL to run at X x Y resolution using
your (cool and useful) GlideV2.dll wrapper, then GPL will work just fine
on a multi-processor box?

Sounds interesting.

system for close to three months now using both cobbled together
drivers and the 1.0 3dfx released drivers.<<

Does that mean you've mixed and matched, or you started off with cobbled,
and then moved to the reference drivers when they were released?

Cheers,

Steve.