Very Computer

: Linux is definately slower...other processing going on.  However, with
: Linux, the raytracing can be a background task while you do real work.
: The DOS version dedicates the machine.  Running Povray under Windows
: or OS/2 kills the performance of both Povray and any other application
: that is running.

I can believe that POV under Windows is slow, but everything I've heard about
POV under OS/2 suggests that it's the fastest there is. Is this true or am I
hallucinating?

Happy tracing,
Andy
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Linux is definately slower...other processing going on.  However, with
Linux, the raytracing can be a background task while you do real work.
The DOS version dedicates the machine.  Running Povray under Windows
or OS/2 kills the performance of both Povray and any other application
that is running.

        Jim

This is true of _any_ multitasking environment, not just Windows.

On the other hand, the official DOS compile of POVRay does run much, much
slower under Windows than under "*" DOS.  My solution was to apply
the FTPOV patches and compile the patched version with DJGPP (GCC for
DOS).

The "* DOS" and "Windows DOS Box" trace times of my modified version
always come out within a minute or two of each other on traces that take
around an hour on my 486-120.

Note that running other programs at the same time _does_ impact performance,
but that's just the nature of a multitasking system.  It's not a flaw in
Windows or POV.

-Grinch

I've timed Linux pov to within a percent or two of DOS pov on the same
machine.  Comparing POV running exclusively on DOS and POV running
with light interactive programs on Linux.

With a good task scheduler (which linux has) and as long as you're not
thrashing your disk from swap due to running several things at once,
there will not be a huge degredation of speed.  Of course, if you run
two things that are both processor bound, they'll each run about 50%
the speed.

But if you use a real OS such as Linux, you should not notice an
impact on responsiveness in your interactive programs or in speed in
your CPU bound programs, just because you're running two things at
once.

Anyhow, unless you have two computers (Or N+1 computers, where N is
the number of people who want to do something with a computer at any
given moment), it's always a win to be able to use your computer for
more than thing at once.  Heck, I'm only one person but I'm usually in
the middle of several things when I am at my computer.

Jeff
--

: >I am currious what kind of performance difference is there in Povray DOS
: >vs Povray LINUX.... For instance what times do you get on simple.pov with
: >800x600x16Mc, +A0.0, +J, +R9, +Q9, I am REALLY curious. Thanks!

: Linux is definately slower...other processing going on.  However, with
: Linux, the raytracing can be a background task while you do real work.
: The DOS version dedicates the machine.  Running Povray under Windows
: or OS/2 kills the performance of both Povray and any other application
: that is running.

:       Jim

It may be slower, but at least, it will use virtual memory.  Povray-dos
would not even parse one of the scenes i tried to feed it.  Povray-Linux,
ate it and 19 hours of nearly dedicated CPU time (i re-niced everything
else, and I went to sleep) later I had the now world famous scene of the
two dragons in front of the temple in 1024x768.

--
Francois Labreque          | The surest sign of extra-terrestrial intel-

[sig snipped]

These are based on personal experience, not by concensus. But they are
based on custom compiles (by myself) not the standard binaries. If the
official binaries are fast/slower I can only attribute it to inadequate
compile time optimisations on POVTeam's part. So you may want to take
my results with a grain of salt.

I have run POV under Macintosh, Linux, OS/2, DOS and Windows. I have found
that the Linux version is by far the fastest. Yes, it will run slow if you
are running X Windows on a small machine, but if you have such a small
machine you might as well run POV in the background and log out. If you
have plenty of memory (ie, 16+ MB) the Linux version will run %15 - %30
faster than the DOS version. I have 12 MB on my machine here at home and
run POV in an X Window with no problems or complaints.

OS/2 and Macintosh probably vie for second. It is hard to compare against
Macintosh because it is a completely different architecture, but Macintosh
has perhaps the screwiest memory management scheme which I have found to
often bog down my computer. I compiled POV for OS/2 with EMX/GCC. I used
the standard official binary for Macintosh. I was very happy with the OS/2
version for the time that I had OS/2 installed.

DOS POV, which I compiled with DJGPP, was slower than either Linux or OS/2
versions. I do not know what to attribute this to since I am not a DOS
programmer per se. If it were not for all the modellers available, DOS would
be my last choice of an environment to develop POV scenes in.

I have also found the same results with Polyray DOS and Polyray Linux. I
think in general that compute intensive tasks will be faster under Linux.
Especially so if you have a FPU.

Take it for what its worth,
Thomas

--
/------------------------------------=----------------------------------------\

|    http://www.bga.com/~amadeus     |   could just look at the source code.  |
\------------------------------------=----------------------------------------/

I recompiled standard POV 2.2 for my OS/2 setup using Watcom v10A, and optimised for Pentium.
There used to be a set of benchmarks floating about using the standard Skyvase scene as a
benchmark. I tested my home compile on this and came up with the following results :

O/S               POV Version          Time
---               ------------         ------
DOS              PentPOV               6m 33s
OS/2             Home Compile        6m 41s
DOS              Official 2.2             7m 12s
OS/2             FTPov21                7m 25s
OS/2             POVOS2                 7m 50s

This was on a P90, 32Mb machine, with no other programs running under OS/2.

Now I'm a great fan of OS/2 so I stick with my home brew version, but draw your own conclusions.

Steve Root

says...

Quote:

>Linux is definately slower...other processing going on.  However, with
>Linux, the raytracing can be a background task while you do real work.
>The DOS version dedicates the machine.  Running Povray under Windows
>or OS/2 kills the performance of both Povray and any other application
>that is running.

>        Jim

Linux is definately slower?!?!?

I've made a test earlier this year with exactly the same scene/options
under DOS / Windows / Linux. Always using the official compile (DOS
compile also under Windows). And now guess what: under Linux my trace
was done in 10% less the time then under DOS or Windows. Just because
it traced under a different (good :-) OS. And I could have - as you
stated - do some real work while tracing.

Did you made tests? (No flame intended ;-)

Happy tracing everybody!

George
--


8303 Bassersdorf I-ooO-()-Ooo-----------------------------------------
Switzerland      I     Linux is the best invention since sliced bread!

optimised for Pentium.

Quote:>There used to be a set of benchmarks floating about using the standard
Skyvase scene as a
>benchmark. I tested my home compile on this and came up with the
following results :

>O/S               POV Version          Time
>---               ------------         ------
>DOS              PentPOV               6m 33s
>OS/2             Home Compile        6m 41s
>DOS              Official 2.2             7m 12s
>OS/2             FTPov21                7m 25s
>OS/2             POVOS2                 7m 50s

>This was on a P90, 32Mb machine, with no other programs running under
OS/2.

>Now I'm a great fan of OS/2 so I stick with my home brew version, but

draw your own conclusions.

Quote:

>Steve Root

I tend to use the linux version of POVRay because linux's virtual memory
scheme is much better designed than any of the windows, or OS/2's. Of
course that's primarily because the OS uses so much less memory.

For example : I have a 133 mhz pentium with 32 MB of RAM. I get
pocketwatch off of ftp.povray.org, and thought I was going to trace it
with the win32 version under win95, so I could do some game playing,
programming etc. while that really long raytrace was taking place. It
turns out that pocketwatch takes a LOT of memory for POVRay to hold it.
Windows became abysmally slow, and shortly I gave up trying to do other
things because it was swapping constantly. I left it running over night
and discovered that it had only finished 22 lines!! At that point I gave
up and switched to linux. Linux finished the entire 1024x768 trace (no
antialiasing, quality 9) in about 40 hours. Compared to the 22 lines
windows 95 finished in about 8 hours!

Running 'top' during this process I could see that pocketwatch took a
total of about 35 MB of memory. I'm not sure what DOS would do in this
case. I've never even tried the DOS version.

sidenote: I don't normally run swap at all in Linux I added it just for
POV ray. Even though Linux must have had to do a lot of swapping, the
system was still responsive, running X and FVWM and Netscape and stuff.

        George Pang

 >
 >: >I am currious what kind of performance difference is there in Povray DOS
 >: >vs Povray LINUX.... For instance what times do you get on simple.pov with
 >: >800x600x16Mc, +A0.0, +J, +R9, +Q9, I am REALLY curious. Thanks!
 >
 >: Linux is definately slower...other processing going on.  However, with
 >: Linux, the raytracing can be a background task while you do real work.
 >: The DOS version dedicates the machine.  Running Povray under Windows
 >: or OS/2 kills the performance of both Povray and any other application
 >: that is running.
 >
 >:  Jim
 >

Quote:>It may be slower, but at least, it will use virtual memory.  Povray-dos
>would not even parse one of the scenes i tried to feed it.  Povray-Linux,
>ate it and 19 hours of nearly dedicated CPU time (i re-niced everything
>else, and I went to sleep) later I had the now world famous scene of the
>two dragons in front of the temple in 1024x768.

Strange Jin, I never had a problem getting Povray-Dos to use
expanded memory and gen some really large images (try 3400 x 2400)
This took days (old cranky 486), but is used all 16 meg (or it
had it available, dont recall how much it really used)

------------------------------------------------------
John Andersen
Juneau, Alaska

POV-Ray for DOS defaults to 3Meg extended menory usage. If you have more memory
than this, or want to use virtual memory, use POVMOD (in the POV-Ray directory) to
tell POV-Ray to use more memory. I think the MAX is 19Meg. This will allow you to
parse those REALLY large Inc and POV files.