Comments on: New PhysX FluidMark 1.2: First Tests

By: cesimbra

cesimbra — Thu, 18 Mar 2010 16:48:11 +0000

Zogrim, thanks a lot for helping me out of my misery — your elaboration and examplification is absolutely satisfying to me and surely far from lame.

Greetings from Germany
Thomas

By: Zogrim

Zogrim — Thu, 18 Mar 2010 16:08:27 +0000

cesimbra
First of all, “Multi-Core PhysX” option has less to do with number of emitters – it just enables app threading, and sets PhysX and rendering in separate threads -that’s because there is such big gain for both CPU and GPU calculations over single threaded mode. On the graph, both ON and OFF sides are using same number of emitters.
“one interesting detail” text and below has nothing to do with those graph, that’s just some of my observations.

“# of CPU cores” option is tricky itself. In PhysX SDK you can run 10 emitters on one core (or GPU), but you can’t set one emitter to utilize 10 cores, and to put load on all cores, additional emitters are added to the scene.

Thus, to gain equality, 3 emitters were used for both CPU and GPU calculations, with multi-core set to ON and OFF – one emitter runs on GPU faster than three emitters on GPU (with equal 15 000 particles number), but it’s not fair to compare one emit. on CPU vs one emit. on GPU, because one emit. on CPU even with multi-threading uses only two cores maximum.

Hope my lame explanation won’t misunderstood you more)

By: cesimbra

cesimbra — Thu, 18 Mar 2010 14:58:40 +0000

Ooops, my usual way of quoting doesn’t work as expected here, sorry, I repost my comment:

In the Global-Scrore-graph GPU-PhysX scales up with Multi-Core-PhysX ‘on’ — in my eyes this collides with
” [...] – fluid simulation is running faster on GPU when one emitter is used, and opposite way – [...] ”

as they should scale down, because in the graph-annotation is written
” Three emitters were used (# CPU cores = 4) [...]”

so it should scale down.

Also, when you refer in the text to the graph, the numbers and the direction of scaling don’t seem to fit

” For example, with one emitter and multi-core PhysX switched to off, CPU simulation results in 36 global points (64 with 3 emitters – on graph above), while GTX 275 GPU – in 247 points (128 with 3 emitters). ”

Perhaps I have a lack of understanding and I’m to blame.

By: Zogrim

Zogrim — Thu, 18 Mar 2010 13:46:52 +0000

cesimbra
It’s checked for sure.. what doesn’t fit for you ?

By: cesimbra

cesimbra — Thu, 18 Mar 2010 13:06:19 +0000

Zogrim, please check graph-data and text, I’ve thought quite some time about it before writing this comment — if I don’t have a massive missunderstanding some things don’t fit together, not only in numbers. ATM I prefer the text-only-version, the graph seems missleading both in numbers and conclusions one would draw.
Anyway, thanks for the information, keep it up!

cu
Thomas

By: JeGX

JeGX — Wed, 17 Mar 2010 16:26:24 +0000

Nice beta test Zogrim! FluidMark will be released tomorrow or the day after tomorrow on Geeks3D. Stay tuned!