P: Slow performance on Xeon CPUs

I have three ssds in my i7-5930K machine and no slowdown in LR, except in rendering previews and exporting over long periods of time.

Keep experimenting, turn everything off you can think of including plugins, navigator, histogram, savetoxmp, etc, etc. Make new prefs file, make new previews, update Win10, disable any strange software, try a clean version of Windows10 without any other software.

Since we don't all have this problem, there must be some incompatibility between LR and your computer, try LR in Win8/7 compatibility mode, look for windows errors, try using MS Resource monitor or Process monitor to see what is happening when it slows down.

Bob Frost

Simon,

I tried the config.lua patch described above.  On my testing (described below), its a definite improvement over running Lightroom without the patch, but not as good as simply setting Lightroom affinity as described by John Ellis (start /affinity F cmd.exe /c "c:\Program Files\Adobe\Adobe Lightroom\lightroom.exe").

However, I got outstanding performance (the best in my testing), by combining the config.lua patch and also setting the affinity for Lightroom to 4 cores (out of my 8).  Results are all below.

I created a test catalog with 40 raw images.  Starting in the Develop module, I simply apply a preset to the image (highlights 0, shadows 100, clarity 20, camera 'natural'), reset the image, then move to the next one.  I do this for 20 images, measuring how long it takes to process the first 5, then the 2nd 5, etc.  Given all the discussion about Lightroom slow downs, this seemed like the simplest way to get repeatable, comparable data on different versions and CPU affinities.

I'm running on an Alienware laptop, with 4 dual-core CPUs (Intel i7-4800MQ @ 2.7GHz)

As a baseline, this is what 2015.10 does without the config.lua patch, running combinations of different processors.  I tested two configurations of 4 processors (mask F (processors 0-3) and mask 55 (processors 0, 2, 4, 6) to see if that made a difference).

Times are seconds to process the first 5 images, 2nd 5, 3rd 5, and 4th 5
no mask = all 8 processors:     26      38      56      80 
Mask 3F =      6 processors:    18       24      35      49
Mask   F =      4 processors:    16       17      23      28 <-- best early performance, but degrades
Mask 55 =      4 processors:    16       16      21      27 <-- best early performance, but degrades
Mask   3 =      2 processors:     24      29      28      29
Mask   1 =      1 processors:     23      25      24      26 <-- no degradation

Now here's what you get with the config.lua patch added in:

no mask  = all 8 processors:    17       20     27      38 <-- Better than before, but not great
Mask   F =      4 processors:    14      15      18      20  
Mask 55 =      4 processors:    15       16     18      15  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I can't say that the difference between Mask 55 and Mask F are real, or just my variation at moving the mouse.  But there's no question that masking from 8 processors to 4, AND adding your patch, produced the fastest performance I've seen.

Elsewhere in the thread, you also asked if anyone knew when this problem started.  It was the upgrade to 2015.5.  I ran 2015.4 until the last week, and never saw any degradation in performance.  I also tested it in the same way as above, and got these results:

no mask = all 8 processors:     22      24      22      21 <-- no degradation

I never upgraded past 2015.4 because, when running all 8 processors, results looked like this (for 2015.5):

no mask = all 8 processors:     26      46      80      117 

Hopefully, these trials can give you some added info to get this fixed permanently.  It would be nice to run Lightroom without having to start with a cmd prompt and a hexadecimal conversion table. 

My system info, from the Config.lua trial, without any affinity mask

Lightroom version: CC 2015.10 [ 1111918 ]
License: Creative Cloud
Operating system: Windows 7 
Version: 6.1
Application architecture: x64
System architecture: x64
Logical processor count: 8
Processor speed: 2.6 GHz
Built-in memory: 16311.1 MB
Real memory available to Lightroom: 16311.1 MB
Real memory used by Lightroom: 1084.5 MB (6.6%)
Virtual memory used by Lightroom: 1245.0 MB
GDI objects count: 667
USER objects count: 2159
Process handles count: 980
Memory cache size: 809.8MB / 3821.7MB (21.2%)
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 663MB / 8155MB (8%)
System DPI setting: 120 DPI
Desktop composition enabled: Yes
Displays: 1) 1920x1200, 2) 1920x1080
Input types: Multitouch: No, Integrated touch: No, Integrated pen: No, External touch: No, External pen: No, Keyboard: No

Graphics Processor Info: 
GeForce GTX 780M/PCIe/SSE2

Check OpenGL support: Passed
Vendor: NVIDIA Corporation
Version: 3.3.0 NVIDIA 372.90
Renderer: GeForce GTX 780M/PCIe/SSE2
LanguageVersion: 3.30 NVIDIA via Cg compiler


Application folder: C:\Program Files\Adobe\Adobe Lightroom
Library Path: C:\Lightroom Catalogs\Test Cat\Test Cat.lrcat
Settings Folder: C:\Users\Mike\AppData\Roaming\Adobe\Lightroom

Installed Plugins: 
1) AdobeStock
2) ColorChecker Passport
3) HDR Efex Pro 2
4) Helicon Focus Export
5) Merge to 32-bit
6) ON1 Effects Standalone 10

Config.lua flags: 
Develop.AdjustMaximumThreadCount = 0.51

Adapter #1: Vendor : 10de
Device : 119f
Subsystem : 5ae1028
Revision : a1
Video Memory : 4026
AudioDeviceIOBlockSize: 1024
AudioDeviceName: Speakers (Realtek High Definition Audio)
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 48000
Build: LR5x8
Direct2DEnabled: false
GL_ACCUM_ALPHA_BITS: 16
GL_ACCUM_BLUE_BITS: 16
GL_ACCUM_GREEN_BITS: 16
GL_ACCUM_RED_BITS: 16
GL_ALPHA_BITS: 0
GL_BLUE_BITS: 8
GL_DEPTH_BITS: 24
GL_GREEN_BITS: 8
GL_MAX_3D_TEXTURE_SIZE: 2048
GL_MAX_TEXTURE_SIZE: 16384
GL_MAX_TEXTURE_UNITS: 4
GL_MAX_VIEWPORT_DIMS: 16384,16384
GL_RED_BITS: 8
GL_RENDERER: GeForce GTX 780M/PCIe/SSE2
GL_SHADING_LANGUAGE_VERSION: 4.50 NVIDIA
GL_STENCIL_BITS: 8
GL_VENDOR: NVIDIA Corporation
GL_VERSION: 4.5.0 NVIDIA 372.90
GPUDeviceEnabled: false
OGLEnabled: true
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