Low Thread Pritrity

[clubber2k]

I found this topic in relations to many issues, I would like to know more.

 

setting VRAY to a low thread allows me to do other things while rendering - right?

 

but,

 

how does it effect render time? drops 50% ? or changes only when I do something else on the computer?

 

if I have a big render that tends to crash - will setting it to low thread help the cpu escape the crash?

 

I have a core2duo, setting a low thread means only 1 core is being used or does one not have anything to do with the other ?

 

anymore tips and knowlage on saving cpu avoiding render crash and low thread are welcome

 

Thanks.

[BrianKitts]

setting VRAY to a low thread allows me to do other things while rendering - right?

 

yes

 

how does it effect render time? drops 50% ? or changes only when I do something else on the computer?

 

it only drops it enough to give enough room for the other processes to occur simultaneously. So if checking your email is eating up 5% of your processing power than vray will approximately be operating with the other 95%

 

i say approximately because there will be other resources utillizing process so it could be down around 92% or so.....

 

if I have a big render that tends to crash - will setting it to low thread help the cpu escape the crash?

 

probably not

 

I have a core2duo, setting a low thread means only 1 core is being used or does one not have anything to do with the other ?

 

it will continue using as many cores as it can.... see answer to question 2

 

anymore tips and knowlage on saving cpu avoiding render crash and low thread are welcome

 

saving CPU won't save you from crashing. adding more RAM on the other hand will do wonders for you.

[clubber2k]

Wow, Thanks for that in depth answer Brian!

 

one last question you opened up. I have been living on the assumption that workload and performance is a matter of RAM. but the render itself is at least 90% CPU power.

 

what (in avarage) is the standoff between cpu and ram during rendering?

when does the render take high cpu and when does it need more ram or are they needed to the same amount? - probably not the case.

 

maybe for the following:

-if the crashes start at the beginning (barely starts).

-while changing a pass or GI engine. (mid render)

-really latter on - or near the end.

-other.

 

Thanks!!

 

so much learned,

Yuval.

[BrianKitts]

When rendering your cpu's should always be hitting near 100% usage minus any other occuring processes. (assuming you're software can utilize multiple cores which max does)

 

Your CPU probably will not make you crash during rendering unless you have faulty hardware. With the exception of if you have a corrupt object in your scene it is almost ALWAYS running out of RAM that makes you crash.

 

If you crash at the beginning, it probably loaded all the geometry in the scene into the RAM then tried to allocate enough RAM for your frame buffer (image) and ran out of RAM or it didn't even make it that far and ran out from all the geometry in the scene so you crash.

 

If you crash when changing passes, most likely in addition to the RAM you ate up for loading the scene and saving room for the final image, once it started saving the prepass maps into the RAM and it ran out so you crash

 

If you crash latter on or near the end, the machine ate up all the RAM saving out the image and you crash.

 

So like I said it's more RAM that will save you. Ask anyone who's jumped to a 64bit operating system with at least 6 or 8 gigs of RAM. You really don't crash anymore when rendering, you're more likely to crash when modeling cause you did something goofy.

 

I honestly never even thing about the processing power when I'm rendering, unless I'm multitasking and trying to photoshop, or work in premiere while rendering.

 

If your find yourself crashing a lot keep the process manager open and watch your amount of available RAM when it hits 0 and max closes, you'll know why.

Edited July 14, 2009 by BrianKitts

[clubber2k]

Thanks Brian!

 

you really go the whole 9yards.

 

Learned allot, now I wish I spent a tad more on hardware a few months ago..

 

Anyway, I have taken all action such as the /3g switch and removing all shaded views and giving it another go.. this time I'm monitoring the RAM, the interesting part is that for a while now it doesn't even go above the 1GB of ram (and I have 2, could that be?).

 

maybe the crashs will come in the passes or saving cause the rendering doesn't take all that much.

 

Yuval.

[BrianKitts]

no problem, I get bored when test rendering materials

 

also don't forget that the best thing you can do with vray when you find yourself crashing due to lack of ram is to render out to a .vrimg. that used to be the only way to get really high res renderings without crashing.

[clubber2k]

Thanks for sharing all your great knowlage Brian.

 

I keep noticing that my ram commit charge doesn't go above 1.1GB (out of 2.1),

1st of all that might mean its not a ram problem right? a model problem? It renders in lower ress though..

2nd, why doesn't max fully utilize my ram? how can I make it take as much as needs?

 

right now I'm trying to render it in parts using blowup, I notice that during render time freezes (task monitor shows everything is o.k.) and after a few min's time returns to count. whats up with that? now I'm thinking that maybe some of those crashes weren't even crashs, just the timer stoped moving for a while..

 

Yuval.

[Ernest Burden III]

maybe the crashs will come in the passes or saving cause the rendering doesn't take all that much.

 

That makes it sound as if you are rendering to an .avi or QT. If so, instead render to sequential TIF or PNG or similar.

[clubber2k]

Thanks for joining in Ernest, I'm still light years away from animating

It's a single frame and save is set to tga (for alpha) tryed JPG too don't think it matters that much..

 

What I keep noticing is that the render time isn't steady, Especially in last "Rendering" phase (although in light cache as well..), it freezes/sleeps for a while and then keeps counting leaving my wondering when if ever it will finish

 

I wounder if there's some power-full pre-render time calculator that gives you an accurate estimate, this current image started as 1hr and now went up to 4+

thats time I currently don't have, If I knew that, I would have let it start - but now, I don't want to waste all the time gone ... ahhh....

 

anyway, why does it freeze?

[BrianKitts]

do you have a lot of proxies in the scene? best I can think of is that is that it's loading/unloading geometry, typically it doesn't "freeze"

 

if that is the case try increasing the dynamic memory limit.... although with only 2 gigs of RAM you wouldn't be able to raise to too much.

 

the estimate is only done as a percentage complete on the image, so lets say you're rendering top to bottom of an exterior, it could knock out the entire top half of empty sky in 5 minutes, and the estimate would say 10 mins total, then you get down to a bajillion proxies and all of the sudden it grinds to a slow, each bucket itself is now taking 5 minutes because it's loading/unloading all the proxies so many times to compensate for lack of RAM...... then your estimate could jump up to 4 hours.

[clubber2k]

Thats really annoying.. Thanks anyway!

 

while monitoring ram I noticed that there are scenes that eat it all up and crash and some just use allot and go slowly.. and it either this or that..

eigther max uses only 1G of RAM.. or it keeps eating it up until it crashes.

 

Thas a bit funny that there is no middle ground, that max can't pase itself not to eat too much ram before crashsing but thats a diffrent issue..

 

I noticed that rendering in regions helps allot.. Thanks everyone!