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cs6 disk cache performance

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Ronald Anzenbergercs6 disk cache performance
by on Jul 13, 2012 at 4:03:23 pm

hi,

i have recently updated to cs6 which is really cool and fast. everything seems to work as expected, except for the new disk cache.

writing a frame to disk seems to take forever making the function "a bit" useless. given i don't have an ssd in the system yet, writing out a single hd/8 bit diskcache file which has around 8 MB takes around 3 seconds.

so just as a comparison: i can copy a 150 MB file from a networkdrive to the cache disk in about 1-2 seconds.

anybody else seeing this.

oh, i am on windows 7 btw.


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Walter SoykaRe: cs6 disk cache performance
by on Jul 13, 2012 at 5:03:18 pm

[Ronald Anzenberger] "given i don't have an ssd in the system yet, writing out a single hd/8 bit diskcache file which has around 8 MB takes around 3 seconds. "

How are you measuring? Does that include the render time for the frame, too?

The cache does noticeably benefit from an SSD -- lots of random reads and writes can be slow on a mechanical drive, especially if it's in use for other I/O, too.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Ronald AnzenbergerRe: cs6 disk cache performance
by on Jul 13, 2012 at 5:58:20 pm

hi walter,

rendering is not included.

what i did:

create a new project with a single comp and a single layer in it. the layer is a raytraced 3d thingy and renders around 2 seconds a frame.

i deleted all diskcaches and moved to a new frame. when rendering of the frame is done, the preview cache indicator jumps to green and the the harddisk light starts to flash and one can also hear that the hdd is working. after around 3-4 seconds this stops - cache frame written.

there is no other i/o on the drive.

once the cache is rendered, i purge all ram caches. timeline turns blue and i can pretty much scrub through it in realtime refilling the ram-preview (just as you would expect).

the problem is especially visible with with comps that render rather fast. a comp that has around 200 frames and renders around 20 seconds take several minutes to cache (when using ctrl + return) in


i have an anti virus software running which might be the problem ( allthough i deactivated it). i will try uninstalling it all together just to rule it out.


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Brian CharlesRe: cs6 disk cache performance
by on Jul 13, 2012 at 9:26:14 pm

[Walter Soyka] "The cache does noticeably benefit from an SSD -- lots of random reads and writes can be slow on a mechanical drive, especially if it's in use for other I/O, too.
"


Exactly why Adobe recommends a separate drive for the cache. Not the render drive, nor the boot drive or the media drive.



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Ronald AnzenbergerRe: cs6 disk cache performance
by on Jul 13, 2012 at 9:58:12 pm

except for the fact that it is not an ssd, all your other points apply to my drive. and again, i am testing this on single cache files in a very controlled setup. it just has to write a single 8 MB files, and it takes around 3-4 seconds for that!

meanwhile i was able to do a test on a second machine which has a raid0 with two drives, and this performs much better but still not as one would expect. i'd expect a ram-preview to go straight to disc - but it won't.

i did a quick atto benchmark on this machine and it tells me the drive(s) have a write performance of 200 MB/s wih files around 2 MB and still around 9MB/s with files around 0.5 kb which i think is the reason this system performs better.

only thing i could imagine is that ae is writing the files in super small blocks which might explain the weak performance.

i can't do a test on the other system rit now, but i will keep you posted.

has anybody else tried to use this feature?


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Walter SoykaRe: cs6 disk cache performance
by on Jul 13, 2012 at 10:28:31 pm

If I put the cache on a mechanical disk, I hear it crunching long after the preview is finished. Perhaps it's possible that writing the cache to disk is just a low priority.

That said, I don't think you're measuring the speed of the cache meaningfully. It doesn't matter how long it takes to write the cache to disk -- it matters how quickly the cache (in both RAM and on disk) is recalled as you work to save you time instead of re-rendering computationally-expensive frames. If you turn the cache off, you will see performance suffer.

I'm doing a writeup on the new caching features -- I should have it out soon.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Ronald AnzenbergerRe: cs6 disk cache performance
by on Jul 14, 2012 at 12:35:03 am

so you are telling me that you have the same behaviour when using a normal hdd and when using an ssd it works as it should?

sure it makes sense even if the writing of the files takes long, but i also do client-sessions which actually worked great with earlier versions of ae, but this would be a killerfeature, if the caching would happend right away.

in demo videos i have seen, it seem to work that way.


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Jesse GibsonRe: cs6 disk cache performance
by on Jan 9, 2013 at 11:43:42 am

Hi Walter - did you ever get around to publishing that write up you mentioned on disk cache issues? I'd love to have a read.

Cheers
Jesse


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Walter SoykaRe: cs6 disk cache performance
by on Jan 9, 2013 at 8:15:58 pm

[Jesse Gibson] "Hi Walter - did you ever get around to publishing that write up you mentioned on disk cache issues? I'd love to have a read."

Sadly, no -- it's still half-finished -- but thank you for the reminder!

Is there a quick question I can try to answer for you?

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Jesse GibsonRe: cs6 disk cache performance
by on Jan 10, 2013 at 12:06:16 pm

Hope it was a useful reminder, not the kind you get from your mother to clean up your room :)

I was primarily interested in understanding more about the process so I can optimise my system. I've just switched from Mac to PC for a new job and I want to spec my machine out as well as possible (within budget of course).

Currently I'm on a Dell T3500 with a Nvdia Quadro 4000 and 8GB of RAM. I have a RAID striped 2TB internal media drive (currently unsure of the specs on that but trying to find out more). I'm in the process of adding another 12GB of RAM but I'm just wondering how much performance gain I'll get from looking at another internal drive - probably an SSD - as the disk cache drive.

Any advice would be greatly appreciated.

Thanks
Jesse


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Donald RileyRe: cs6 disk cache performance
by on Jul 14, 2012 at 4:30:30 pm

Hi Brian

I'm new to AE and not real clear on the setup for Disks. This is what I have.

Boot Drive just the common cache

Raid #1 (external) Project folder and Preview Folder (Render right). and the Global Cache (500G large)

Raid #2 (external) Media All of it Video, Audio and pics.

Should I move the Global cache to another seperate Raid and do you think I should move the Project files back to my Boot Drive.

This would be huge for me I keep changing things around but I may not have it right yet. Thanks so much.

Don
MP 12 core 2.9 GHZ
32 GB ram
Quadro 4000
2 Ext. Raids 180 Mbps


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