"Theo Gottwald *" <The### [at] t-onlinede> wrote:
> Hi Anto,
>
> Here are my numbers:
>
> skyvase.pov rendered in 1024x768 in 1 Tiles (-) from 08-23-2003 / 11:53:28
> to 08-23-2003 / 11:54:15 (47).
>
> skyvase.pov rendered in 1024x768 in 2 Tiles (H) from 08-23-2003 / 11:54:22
> to 08-23-2003 / 11:54:58 (36).
>
> skyvase.pov rendered in 1024x768 in 2 Tiles (V) from 08-23-2003 / 11:55:04
> to 08-23-2003 / 11:55:52 (48).
>
> skyvase.pov rendered in 1024x768 in 4 Tiles (H) from 08-23-2003 / 11:56:10
> to 08-23-2003 / 11:57:02 (52).
>
> However - all rendered locally with my 2 CPU's. You see the Overhead when I
> make 4 tiles makes it even slower then when I render this in 1 tile.
>
> In one sentece: Scenes which need only very short rendering (30 Seconds) may
> not be the best candidates for SMPOV and Hyperthreading. I have counted that
> even before the second instance starts up, 4 Seconds are gone.
>
> Your numbers:
> 38 Second - 29 Seconds = 9 Seconds diffrence. How long does it take for your
> POV-Ray to load?
>
> Remeber we load two instances of POV-Ray. Secondly they start up and load
> the POV-File.
>
> Did you include the "loading time" while measuring the 29 Seconds?
> Maybe in that case POV-Ray was already loaded and shurely even the file.
>
>
> Secondly Pictures which need more time to pre-process then actual render
> time
> maybe not the best candidates for "Tiling" in Hyperthreading Systems. (=
> rendering them in pieces).
> (General statement)
> The point is that we start 2 instances of POV-Ray and EACH does the full
> Preprocessing.
>
> If you would have a time win of 20% for using the Hyperthreading, you have a
> loose
> for doing the Pre-Processing two times. I have no idea if "preprocessing"
> can be "hyperthreaded" or not.
> On my Dual-Athlon i've found that Preprocessing produces nearly no CPU-usage
> (I used PartixGen - very intresting and fully distributable) - so I would
> say give it a try.
>
> With real SMP-Systems (my Athlon here) the situation is diffrent.
>
> 2. SMPOV and the Renderagent need also some calculation- and reaction time.
>    They are primarily made for pictures which need long time to render so
>    the "builtin reaction-times" are rather slow to save CPU-time.
>   Reaction time is, between SMPOV giving the Orders for Rendering out till
> the RenderAgents react.
>   Secondly till they notice that POV-Ray is ready. Then thirdly SMPOV has to
> get a message that all
>   the tiles are ready. And fourth it has to start PicPender.exe to "put al
> lthe tiles together".
>   There are several reaction times that may add up to 5 Seconds. Add your
> loading times and some
>   time for "Preprocessing"
>
> 3. Two instances of POV-Ray are started. (=Loading time for POV-Ray).
>
> 4. To find out where the times are, you can render it with SMPOV, make the
> "Tiling" on 1
>    (so there will be only 1 instance started). Then make a second try (tling
> on 2) - try "H" and "V"
>    there are diffrences. Then you have numbers in the log-file. These
> numbers include some overhead,
>    but at least you are shure the settings are really the same for all runs.
>
> Keep me informed if you make a second try.
>
> --Theo
> -----------------------------------------------------------------------
> Distributed Network-Rendering or Local SMP-Rendering. With SMPOV and
> POV-Ray 3.5. * Download free at: http://www.it-berater.org/smpov.htm


I tried that, but I can't seem to get SMPov to run good on my P4 with HT, he
still only renders on one of the two virtual CPU's.

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