rec.autos.simulators

Recently i stumbled on this feature: press letter O in the race and the
puter reports "Processor Occupancy"...

BUT:
What is it? I would understand if the numbers returned when using this was
somewhere between 0 and 100 percent. Mine are 210 to 220 percent. I don't
get it! Anybody out there who knows?

Happy New Year!
Jas

What you have to do is turn off some of your graphics options. Don't worry,
I was getting over 300% occupancy sometimes on my old 486DX2 system, and
it's still valid to see over 100% occupancy in even the fastest systems out
nowadays, because the processors are just simply behind the software in
this day and age. It goes like that, sometimes the hardware is way faster
than the software, and then all of a sudden the software destroys the
hardware.

                                        Yousuf Khan
--
Yousuf J. Khan

Ottawa, Ont, Canada
Nation's capital

Understanding the occupancy measurement is actually one of the most
important things in order to get GP2 to run properly. Briefly stated,
you can get the occupancy anytime when you are playing the game by
pressing the "o" key. It then gives you a number which indicates
the percentage of processing power which is being used to display
the game. If it is under 100%, then it means that there is processing
power to spare. If it is over 100%, it means that the computer does
not have enough processing power to display the game with the detail
options and frame rates you have selected in the option screen.

THIS IS IMPORTANT. GP2 is more primitive than most other games in
terms of how it handles a lack of processing power. For instance, in
Indycar 2, if the computer does not have enough processing power to
display all of the required frames, it firstly stops applying some
textures to reduce the processing load (depending on the options you
choose in the setup screen). If this still does not lessen the
processing load enough, it then also reduces the number of frames
per second it displays, so that the game is still able to display
what it is required to display in "real time" (ie, irrespective of
the processing load, one second of game time is equivalent to one
second of real time, and it will always take the same amount of
real time to travel down the main straight, for instance).

GP2 is different. Irrespective of the processing load, it does not
compensate for this by changing either the graphic details or the
frame rate. It will always display what you have chosen in the setup
options. Therefore, if the processor does not have enough processing
power, then it will still do all of the calculations but will not be
able to display them as fast as they should be if they are
representative of how fast things should be occurring. Therefore,
the game will actually slow down! In other words, whereas usually
it would take 3 seconds (in real time) to go from one corner to another,
this can actually increase to 6 seconds even though in the game the
car's speed is just the same.

This is most noticeable at the start of the race and into the first
corner, where occupancy can go up to 400% or higher and the game almost
seems to slow down to a crawl for a while. This is largely due to a lot
of the cars producing smoke from their tires (the smoke effect is very
processor intensive) and the cars trying to sort themselves into a
single file. Once they have done this, the occupancy should return to
normal levels.

Therefore, it is best to run GP2 with the occupancy rarely exceeding
100%, as this then means that game time will closely mirror real time.
To do this, you should choose a frame rate which is at least a couple
of frames (if not much more) below the estimated frame rate. Also, a
frame rate below 16 starts to become to jerky (various people find
different frame rates to be "barely acceptable"). Anyway, once you
have decided on what frame rate you want to run at (eg, 16), you
should change the detail options until the estimated frame rate is
at least 18 to 20 using whatever graphical options you think is the
best trade off (considering the speed of your computer). You should
then start a practise run and make sure the occupancy is around
70-80% on a clear track. This should then be alright as it gives a
bit of leeway for occupancy to increase when you are in traffic,
as well as processor intensive parts of the track.

You will find that processor occupancy will vary both at different
points on the one track (as some parts have more objects to draw)
and vary greatly across tracks. In particular, the occupancy at
Monaco will be much higher than any other track (Monza is also
relatively processor intensive, surprisingly). Therefore, detail
options set for one track may not be appropriate for another track.

rgds
Marc Biesmans, Essen, Belgium

 It goes like that, sometimes the hardware is way faster

Dennis,

Thanks for the excellent explanation.
A related question to this is, what happens when we couple two PC's to have
a multiplayer game (as we often do, BIG fun).
Both PC's have different processors. If the game slows down on one PC -in
your example you indicated that a 3 seconds part can take double the time
if the processor is overloaded- I assume that the other one will follow
this.
In other words, in a two PC situation it has no advantage to play on the
fastes PC ??

Is that correct ?

Martin

snip, snip

snip, snip

Try this out....make a timed test lap...save this HOTLAP. Replay it
with a stopwatch in your hand...time the lap using your stopwatch. If
your stopwatch showed a longer time than the laptime indicated by your
***pit timer then you have too much graphic detail selected to run in
realtime....reduce the amount of graphic detail so that
Realtime=Laptime...you'll find that the occupancy numbers will be
below 100% and the car handling response will improve!

Another slant would actually be that it is very clever <g>. Dropping
frames is as much of a bummer if it's just before a braking point as a
slowing down of the game time :(

Both the Geoff Crammond "slow time" and Papy's "drop frames" approaches
have pros and cons. At the end of the day however you need to come up
with a setting that will give a _consistently_ fast frame rate in Papy's
sims or a fast frame rate in real time for GP2 - this is the only way in
which you can hope to drive a sim consistently quickly.

Cheers,
Richard

Prosessor occupancy should not very often exceed 100 percent because it
causes the game slow down. You should lower your detail settings or frame
rate. My personal opinion about frame rate is that it must be at least
19.6 or higher.

0-100% - The frame rate is being acheived.
100+%  - Not quite. You'll better turn off some details or lower the
frame rate.

BTW: This feature was already present in F1GP1.

Regrads,
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I've written a (moderately technical) explanation of the realtionship
between frame rate and occupancy in my GP2 FAQ, at
   http://www.simracing.com/onestop/gp2/faq/
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