CPU dropoff during lightmap ir calculation

[TRGraphics]

Has anyone else noticed that when using lightmap in the secondary bounce that during the ir passes that the cpu usage drops by 10-15%. I have a dual 2.8 xeon 2 gig of ram and thats a lot of horsepower thats not being used. When calculating the lightmap its 100% usage and when rendering its 100% usage. Very strange.

This only happens with lightmaps!

Tony

[natty]

Havent noticed ... i'll check tomorrow

[vlado]

Re: CPU dropoff during lightmap ir calculation

Has anyone else noticed that when using lightmap in the secondary bounce that during the ir passes that the cpu usage drops by 10-15%. I have a dual 2.8 xeon 2 gig of ram and thats a lot of horsepower thats not being used. When calculating the lightmap its 100% usage and when rendering its 100% usage. Very strange.

This only happens with lightmaps!

Tony

Does this happen on any scene? Do you have hyperthreading enabled? How much RAM is used when rendering according to the Task Manager?

Best regards,
Vlado

[TRGraphics]

So far it is happening on every scene I've tested. I do have hyperthreading enabled but no crashes or other problems. I've never had any problems with hyperthreading.

The ram usage depends on the scene, of course. One scene I have used 750 meg and another 350 meg. None of the old scenes have gone above one gig of memory usage. The average is about 500 meg of ram usage.

I've tested a dozen or so scenes and their all having the same issue. I created a new scene with just a bunch of spheres and glossy reflections with the latest build to make sure it was not a compatability issue but still the same problem. This scene used 1.3 gig of ram with no crash but the cpu usage for ir map dropped to between 86% - 92% while calculating.

Overall, the new build is extremely stable on my system. The most stable by far of any I've ever used.

Tony

[vlado]

Might be because of the hyper-threading; will make a few tests here.

Best regards,
Vlado

[Randy]

I have exactly the same problem here, machine is a dual xeon 3,2 with 2gb ram, HT of course is enabled.

[natty]

nope its not doing that here ..... on my home pc which a dual AMD, havrnt tried the work pc yet

[timmatron]

Right now i'm experiencing an average of only 60% usage with HT on while calculating my IR map. No wonder its taking so long.

[TRGraphics]

Tim, which version are you using?

I tried a scene with the latest internal build and cpu was maxed out while calculating the ir map. I tried both quasi monte-carlo and lightmaps.

My system-Dual 2.8 xeon with hyperthreading and 2 gig of ram.

It looks like they fixed the lightmap problem.

Tony

[timmatron]

I think the problem went away. I shut everything down and reloaded Viz & got back to 100%.

Still wasn't able to fix my render strips problem mentioned in the other thread though.

[davidaleon]

Its good to see this is abnormal. I did a big GI box last night (3072x2304) which took 44 minutes plus on my dual OC XEON ring (2.8->3.25). I re-rendered under finalRender (which was hardly able to keep up with 1.09.03r) and it spanked 1.45.07. It finished the scene in just over 20 minutes.

I investigated and it seemed that all of the time was absorbed by the Irradiance map calc phase. I got only two tiny buckets despite the fact that I have hyperthreading enabled, and I set my buckets for 128x128. I should have seen four of those bad boys wizzing around fast. Instead I saw two creeping around making triangles out of squares.

Of course a bucketed calc phase is different from what we saw before in 1.09 where we had a couple of scanlines move from top to bottom and bottom to top.

[moshenko]

One thing to check out might be the bitmap pager. See this thread:

http://www.chaoticdimension.com/foru...pic.php?t=8319

I encountered similar problems and resolved them by disabling bitmap pager - something a reinstall would do automatically.

[percydaman]

im having the same issue. no problems until I set the resolution to 3000x and now its stuck at 55% to 62% during imap calculation. I have dual athlon MP's

[timmatron]

Moshenko: THANKS!

That really did the trick! To all others who try turning off bitmap paging, just make sure you close & restart Max/Viz before trying to re-render.

[percydaman]

Any idea what to do if you dont have a bitmap pager line?