Post by Zach Deedler
I must be fairly confident that switching to linux will solve some of our
paging problems before I recommend it to my boss.
I think in the end you'll just need to do side by side
performance/quality tests, and you'll need to come up with a metric or
set of metrics to test them. Dual booting a single system is probably
a good way to achieve like for like comparison.
For vis-sim the measure the number of frame drops from your target
frame rate is probably one of the most useful ones.
If you are already hitting a solid frame rate then seeing how far you
can up the LODScale before frame drops start occur could be another
good metric. This could give you a feeling for how comfortably the
system copes with the load.
The visual quality side is probably just done to how well FSAA and
anisotopic filtering scale on each OS, and this is almost entirely
down to the driver, and if your using NVidia cards there is good
chance that visual quality will be identical. Curiously under Vista
the FSAA does seem to have suffered relative to XP, not sure why yet,
but it could be down to the extra demands on GPU memory that Vista
makes. Visita only matters though if you are buying a new machine for
a sim as I can't image many upgrading to it for simulator.
Once you have your standard set of tests together you could start
looking at various things you could tweak on the linux side to get
best performance from it. For instance you could cut back on all the
services running on the machine, just run what is required for the sim
and no more. One thing I've found on my system that is important for
solid performance is to remove the powersave demon as this consumes
CPU cycles and also interrupts the CPU erratically.
You can also try out different file systems, some may favour the type
of disk reading that paging demands. I haven't experimented with this
yet, but its something that I've long been curious - which file system
to recommend for paging. Perhaps others in the community might have
some insight in this.
Finally there are the real-time OS versions of Linux.
Over all I think Linux is very compelling platform for vis-sim apps,
its very customizable, the basic components of the OS are vis-sim
friendly - good file systems, real-time kernel availability,
multi-processor support, ability to cut the running services to bare
minimum. If you match up this against XP, Vista and OSX what you have
isn't something that you isn't in great shape to start with, and can't
be customized extensively to get it in to good shape.
Post by Zach Deedler
Also, if anybody has any suggestions on how to improve paging on windows,
I'd appreciate it. I've tried changing the size of the paging file, and
such but haven't had a lot of luck.
IDE disks do make more of demand on the CPU than SCSI so this might be
In the end though, the same hardware under Linux has a good chance of
out performance due to better file systems and multi-processor
Long term Linux is where I think you should be, but migration isn't
always painless - if all the components you rely upon aren't available
you need to get them ported over, there also the need for learning new
ways of working. Once migrated and up to speed there won't be any
looking back - especially as you arent' locked into one vendors future
OS evolution - you can pick the distributions or even build your own
distributions that perfect fit with your needs.