Lr Classic and graphics processor

[rdonson]

I've remarked prior to Lr Classic on Lr CC 2015 how I've had to go to "Preferences, Performance" and disable the graphics processor.  It was horribly slow after doing extensive work with the brush tool.

Well.... this is one aspect of performance not improved for me with Lr Classic.

My wife and I both experience this on our machines.

Both of us have 27" 5K iMacs with 40 GB RAM and hefty graphics processors.  My wife's has a AMD Radeon R9 M395 2048 MB and I have the AMD Radeon Pro 580 8192 MB.

Adobe's "Learn More" is of little help to me other than to suggest to disable the option.
https://helpx.adobe.com/lightroom/kb/lightroom-gpu-faq.html

Does anyone know if Adobe is going to work on the graphics processor performance in Lr Classic?  This seems like a leftover from several years ago. 

[Nick Walker]

I also had to turn off GP in Lightroom Classic's prefs until this workaround  https://www.youtube.com/watch?v=qozuHWU60so

In a nutshell download a 28 byte Adobe document (open GL related) from Adobe https://shared-assets.adobe.com/link/082f4efd-be2b-4a84-7dda-5b672f7f766e

On a Mac, copy the document to the main library > application support > Adobe > Lightroom (restart Lightroom for the difference to take effect).

Hope this might help.

[john beardsworth]

The contents of that file, which is executed by LR upon startup:

Develop.PreferOpenGL = true

[rdonson]

Thanks so much, Nick. 

Incredibly simply fix that works.


John,

Thanks for the explanation.



Boggles my mind to wonder why Adobe doesn't include the appropriate detection and fix during installation.  Is Adobe asleep at the wheel (still?).  Stunning.

[jrsforums]

The contents of that file, which is executed by LR upon startup:

Thanks, John.  I have been working well on a Win10 system with nvidia card.  Noticed in LR system info that the card was set at DirectX.  However, I was not having any apparent problems.

Reading the Adobe spec for GPU cards, it appears that OpenGL is important to them as it is mentioned, not DirectX.

So my question....is it best to use this code to force into OpenGL mode?

[john beardsworth]

I really don't know, John. I only contributed to show what the file is doing, but I wouldn't say more without knowing the context which led to it being posted.

[David Eichler]

Turned on the graphics processor on my MBP with LR Classic and finally no performance hit. Not sure at this point if any performance gain, however. Intel Iris Pro GPU.

[MBehrens]

On Windows I suspect that this file would go in the "C:\Program Files\Adobe\Adobe Lightroom Classic CC\Support" folder. Other versions of LR would choose the respective folders. Is this where other Windows users are placing it? Could this line simply be added to the preferences file?

I've been leaving the graphic processor selected, though I don't think I see a huge improvement.

Having this file added, maybe there is some improvement - if it is being recognized - but not enough to rule out "wishful thinking"

Too bad Adobe doesn't provide something more definitive in this area.

[john beardsworth]

Too bad Adobe doesn't provide something more definitive in this area.

Like https://helpx.adobe.com/uk/lightroom/kb/lightroom-gpu-faq.html

The file is called config.lua, a special name for LR. Config.lua's contents can vary depending on what the software engineer is trying to test, so it might enable logging, for example, or here it's switching on OpenGL. It is not intended for general use.

[JeanMichel]

I too have a 27" iMac  5k with the AMD Radeon R9 M395 2048 MB processor. My LR Classic preferences show that and the OpenGL engine. So, in my case LR is aware of what my system has, and I did not have to go about downloading a fix. I have no issues in the developing module.

[rdonson]

I'm glad to hear it didn't affect everyone.

[MBehrens]

The file is called config.lua, a special name for LR. Config.lua's contents can vary depending on what the software engineer is trying to test, so it might enable logging, for example, or here it's switching on OpenGL. It is not intended for general use.

Yeah, I got the file from the messages above. I was just wondering where it would need to be placed on a Windows system. I only saw a path for Mac.
The FAQ link I'm familiar with. It doen't mention the config.lua file that I've seen... though I have not read every word on the page either. I may be missing something..

Thanks!

[Chris Kern]

I also had to turn off GP in Lightroom Classic's prefs until this workaround  https://www.youtube.com/watch?v=qozuHWU60so

In a nutshell download a 28 byte Adobe document (open GL related) from Adobe https://shared-assets.adobe.com/link/082f4efd-be2b-4a84-7dda-5b672f7f766e

Oddly, this fix—forcing Lightroom to bind to the OpenGL graphics shared library—originated as a way to work around an abnormal exit (Lightroom "crash") on Windows with Microsoft's Direct X and was later proposed as a way to deal with a Develop Module display issue on MacOS with Apple's Metal graphics library.  No mention at either of those links about it resolving the performance problems many users have experienced on both platforms with GPU acceleration enabled.

I have a feeling that using a graphics subsystem as a secondary general-purpose processor has turned out to be considerably more complex than the Adobe developers thought.

[Hoggy]

Yeah, I got the file from the messages above. I was just wondering where it would need to be placed on a Windows system. I only saw a path for Mac.

It goes in the 'root' of your presets folder.  You can use "showLR presets folder" within preferences.

On mine, it would be:
C:\Users\[username]\AppData\Roaming\Adobe\Lightroom\config.lua

[Denis de Gannes]

I too have a 27" iMac  5k with the AMD Radeon R9 M395 2048 MB processor. My LR Classic preferences show that and the OpenGL engine. So, in my case LR is aware of what my system has, and I did not have to go about downloading a fix. I have no issues in the developing module.

Same here, never had a problem with Lightroom with my Mac since mid 2015 when I purchased my iMac. I have my GPU active and do not see and significant difference if it is on or off.
Based on what I see on the forums on the net its an irrelevant issue, if it works for you leave it on otherwise turn it off. Maybe some day it may have some relevance.

[dbritch]

I think it's unfortunate that the Adobe engineers are using OpenGL rather than OpenCL. That (and some of their comments) indicate that they are using GPU acceleration only in rendering for display, not to accelerate their processing algorithms. That's where there is real potential for acceleration.


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[John Cothron]

I'm glad I ran across this thread.  It was not recognizing my card either (Nvidia 1060).  I just put in the config file and it is significantly improved with GPU acceleration. 

[Chris Kern]

I think it's unfortunate that the Adobe engineers are using OpenGL rather than OpenCL. That (and some of their comments) indicate that they are using GPU acceleration only in rendering for display, not to accelerate their processing algorithms. That's where there is real potential for acceleration.

Well, admittedly I have no knowledge of Lightroom's internals, but from an end-user's perspective the bottleneck in the Develop Module has always been rendering—especially when making local adjustments, zooming to 1:1, and performing other drawing operations that are computationally expensive.  Again, just an impression, but LR otherwise seems to have enough CPU cycles to do what it needs to do on a modern multi-core machine: when it blocks, it almost always seems to be when it is updating the display.  I presume the Adobe developers use DTrace and something similar on Windows to determine for what functions greater parallelization would be useful.

[Tim Lookingbill]

Going by that linked YouTube video showing the shadow rendering differences between Library & Develop modules (same problem I have in non-CC LR4-fixed by my loading a matrix color working space in Soft Proof left on in Develop module): I would think it important to test the OpenGL 28K file "hack" or any other fix by examining the black point and rate of ascending shadows in a color managed 21 step wedge grayramp in both modules AND comparing side by side in a non-Adobe third party color managed image viewer. I'm on a Mac so I use Preview.

I don't use LR at all because of this and other interface issues but that YouTube video was new to me because what I've read in the past were only performance speed issues and NOT the changing previews between the two modules.

I just can't believe that all it took was to load a small file to fix this. How is this not a hack?

This has been a very interesting thread and an eye opener on what I thought was a problem that didn't relate to me but now see that in a way it does.

[rdonson]

Tim, for me it wasn’t just shadow rendering.  I was baffled by the lack of detail of the photos in the Develop Module. 

Once the “hack” was deployed I saw the detail again.