Indigo Renderer Forum

Hi all,

i just found out something weird. For some time i was concerned about the speed of my system when it comes to rendering with indigo. (See Specs below)

To analyze everything i started rendering a simple scene i made some time ago.
I used
Ubuntu 8.04 (64bit)
Blender 2.47 (64bit)
Blendigo 1.1.7
Blender 1.1.9 (Windows 32bit - Wine)

Here are the results: That means rendering with one thread takes only about twice as long as rendering with four. I dont know if this is a problem of the small caches of the Phenom or a problem of Wine. How is the Scaling on your systems? Is it normal to loose so much Power when four cores are involved?
So to the Point: Is this a Phenom Problem?

System-Specs:
AMD Phenom 9750
2 GB DDR2-800 Ram (Only 1 GB used when rendering this Scene)
Mainboard: Asus M3n78-EH

i believe i scales petty much linear on my intel quad.
ill do some tests tomorrow.

Here is a comparison Chart, which shows actual speeds on the left side while you see expected (linear scaling) speeds on the right side. OK i know i cant expect linear scaling, but nearly.
Here you see that with the expected speed 3 cores should already be faster than 4 cores are actually for me.

They are both competing for the same memory. Try to render a tiny scene and redo test.

Don't you mind sharing the scene?

Deus wrote:They are both competing for the same memory. Try to render a tiny scene and redo test.

Does that mean more ram would definitely help?

Isigrim
I've never use 64bit before, but shouldn't you test your scene with Indigo 64 bit?

Or 32 and 64 bit are pretty much the same in term of memory usage? (Except that the 64 bit can take advantage from more than 4GB of RAM installed.)

Please forgive my ignorance.

In my experience Indigo (and pretty much ANY renderer, unbiased or not) scales almost perfectly linearly when you add cores/threads.

I've never actually used a Phenom, but even on my A64 boxes the scaling works as expected...

@Deus:
i don't quite get this. What do you mean by "both"? Do you refer to the four cores of the Phenom? If this is what you mean, Phenom would be a weird construction. Like building a Car with an immense engine, but without the adequate fuel hose to support it.
But i will try rendering a more simple scene to see if that helps.

@pixie:
Will pack it later and share it here.

@palawat:
I should use the native 64bit Linux version for testing, but there is no such version yet. (I understand that making an extra release for Linux each time is time intense, yet i am looking forward to seeing the new features in a native Linux Version). So i have to fall back to wine to use/emulate the 1.1.9 windows version in Linux. Wine though accepts only 32bit applications at the moment, so you see my problem. I will now do a test-run under 1.09 native linux now to find out the bottleneck.
And afterwards i will get me some Vista 64 this month, to test it all correctly.

@zsouthboy:
another possibility, which seems to be possible so improbable is my mainboard. i use a Mainboard that actually supports CPUs till 95W TDP, but i have a Phenom with 125W TDP. Maybe here could be bottleneck too. (If the next quad from AMD (codename Deneb) isn't significantly faster at rendering, i think i will switch back to Intel).

Isigrim:

Ouch on the motherboard issue, I had heard about that problem.

I think your *main* problem is WINE in this case, however. The extra step there is screwing with your results.

Render the same scene in 1.0.9 and see.

quote zsouthboy, "Ouch"

BTW, your render looks pretty good for a ~120 s/px.

Ok made the test with native Indigo 64bit Ubuntu Version 1.0.9
Seems like it's exactly the same as with Wine and 1.1.9.
Problem remains, so we can exclude Wine from Bottleneck list. (i like this dirty economy talk ) That makes a Scaling of 2,456 from 1 to 4 Threads. Not even above 3
BTW: It's a bit faster because i had to remove Subsurf and displace from the walls, because this is not supported on 1.0.9.


Bottleneck possibilities:
Phenom (Cache)
Mainboard (Power Supply for the CPU)
Ram

Rejected bottlenecks:
Wine

@palawat:
thanks to Ono for that.

If you're using the wrong mobo, then I'm sure it can't be good.

New test, to examine the Mainboards Power Supply for the CPU.
I used Powersave-mode on all cores, so that they stay at 1,2 Ghz while rendering. Scaling factor: 4,50 (What the hell...? Ive got to redo this Test, every Scaling above 4 seems must be wrong...)
That shows: My Phenom cant take any advantage from double Mhz....1,2 Ghz in Comp. to 2,4 Ghz.
Now ive got to test if this is a Cool'n'Quiet (AMD throttling and Power Saving Tech) Problem or a Mainboard one (i think it's the Mainboard). So next test is disabling Cool'n'Quiet. Will post my results later.

The problem is that i bought the Mainboard before all the problems occured and were posted. So i thought, if the CPU is running and stable everything seems to be fine...but as shows now: this was an error!

Here is the test with Cool'n'Quiet disabled. Actually this makes everything even more interesting. While rendering began with 372504,74792 samples / second it dropped constantly afterwards.

So Cool'n'Quiet doesnt seem to be the problem either.
So it becomes more and more obvious that it's the mainboard. I will order one (GigaByte GA-MA790GP-DS4H with a 790GX Chipset) and tell you the results once i get it.
Maybe some 1066Mhz ram as well....hmm don't know, we'll see.

the b1 (and i belive b2) steppings of phenom have some issues that make them underperform a lot (the performance drop is b/c of a bios patch to keep it fixed).

you should use cpuz to figure out which stepping you have first, as that is probably why you are getting funny results.