P: High CPU usage makes it unusable during export

[FeedbackCommunityMember]

After latest Lightroom Classic CC I almost can't work in Lightroom during export as it's using around 90% off mu CPU. Maybe exporting itself is a bit faster but when exporting 2000 pics I'm unable to work for about half an hour as there are huge lags. In the end I would rather prefer slower export working in a background and still have ability to work with pics without such noticable slow down. It was much better balanced before updating to Classic CC.
My CPU: Intel Core i7-6700K (4 cores, od 4.00 GHz do 4.20 GHz, 8 MB cache)

[FeedbackCommunityMember]

I moved from a 2009 Mac Pro to a brand new iMac i9 with 40GB of RAM working off a 1TB SSD.  My 2009 was almost as fast and never had issues like this using the newer LR Classic.  I can't even write a text message and have trouble mousing while trying to export just 800 images.  Same concerns here - I can settle for a slower export. But I can't stop working for hours at a time throughout the day.  My CPU usage on Activity monitor registers anywhere from 750% to +1400% - I don't even know how that's possible

[johnrellis]

"My CPU usage on Activity monitor registers anywhere from 750% to +1400% - I don't even know how that's possible"

In % CPU column of Activity Monitor, 100% = one virtual (logical) core / thread / processor (industry terminology is not consistent).  So on an Intel computer with 16 virtual (logical) cores / threads / processors, the % CPU column could show a maximum of 1600% for Lightroom.

But in the system totals shown at the bottom, System + User + Idle total to 100%.  How's that for confusing?

[johnrellis]

"it is cumbersome to change affinity using Windows Task Manager all the time."

A late reply that might be useful to you and others: You can create a .bat file that will start LR restricted to a subset of virtual/logical processors. For example:

start /affinity fff "c:\Program Files\Adobe\Adobe Lightroom Classic\Lightroom.exe" c:\Users\john\Pictures\Lightroom\Test\Test-2.lrcat

starts LR restricted to 12 virtual/logical processors / threads. The "fff" is a hexadecimal mask specifying the particular processors to use.

@echo off
REM Starts Lightroom with a process affinity. Replace 7 below with 1, 3, 7, 15, 31, 
REM 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, or 65535, to restrict
REM Lightroom to use 1, 2, 3, ..., 16 virtual/logical processors.
powershell "& ""c:\Program Files\Adobe\Adobe Lightroom Classic\Lightroom.exe"""
powershell sleep 10
powershell $P = Get-Process Lightroom; $P.ProcessorAffinity=7; $P.ProcessorAffinity; $P.Id

(The original commands I provided no longer work with Lightroom for some obscure reason I can't figure out.)

[PhilBurton]

Robert,

Can you post the URL to that article.  Thanks.

[garyrowe]

Rikk - Why on earth design a behaviour such that 'After restart lightroom will reach 90 percent but after 10 minutes of working it goes down to 10 to 30 percent.'?

[COBill]

A computer is always waiting on something, otherwise everything would happen instantly. It is waiting on CPU, I/O, network, memory, etc. So when the cpu busy drops from 90% to 30% it is because it is waiting for something else such as reading or writing to disk. 
 
For example, I moved my Lightroom library and catalog to my GoogleDrive folder to have a cloud backup. Then with every update (adjusting a slider, etc), Google locked the appropriate file until the file was uploaded. Otherwise the file could get corrupted. To fix, I put a SSD on the PCIe bus, moved everything except the Lightroom Cache to that disk (dedicated to Lightroom), the cache is on a separate SSD, and use a file/folder synchronization program to periodically sync Lightroom with GoogleDrive. I use Second Copy 9.0. 
 

[Schmidtze]

Hello,

I have the same problem, my PC (a DELL XPS 15 7590 with 32 GB RAM and 2 TB SSD) gets unusable while doing exports. I don't know this behaviour from other applications, working with other software should be possible while Lightroom is doing exports in the background. Of course the computer will get slower, but not unusable. What about a mechanism to lower down the priority when switching to other applications automatically, when Lightroom is losing the focus? Or an option in Lightroom about the priority. I'm working at home at the moment, because of Corona, as a developer for my company. And so it would be possible to do exports with Lightroom while working remote on my office PC. But it's not possible because of this problem. Very very annoying. 

I'm using Lightroom since the first version. In my opinion this problem is new since a few months, maybe...

Best regards
Friedemann

[bob frost]

If you really don't want to try any of the other tips above, why not start your export just before you go to bed?

Bob Frost

[supervova]

I'm expecting it to use all my cores, but not on such priority that I can hardly move my mouse cursor...

[COBill]

UNIX (the OS core of MacOS) is not a priority based, interrupt driven OS. Adobe would have to offer a setting to limit the number of parallel threads. 

[Tr0ttsky]

Bob, some of us use this software professionally and don't want to resort to work arounds. This is a serious issue for heavy users and needs to be addressed by Adobe.

[FeedbackCommunityMember]

Some ideas - update your motherboard as it could optimize how your CPU cores are tackling each IPC (instructions per clock).

Also, try setting the priority level of Lightroom to a lower level.  

It's not a complete fix, but I notice I can still use my computer a bit more while exporting 100+ photos.

[johnrellis]

On most computers, LR is good at limiting its total CPU usage during exports to about 85%, but on some computers, particularly those with a larger number of cores, LR uses close to 100%.  

This performance bug has been around for several years, and it should definitely be fixed. But if you need to get work done while waiting for Adobe to fix it, on Windows you can easily limit LR to use, say, 12 of 16 virtual processors:
https://feedback.photoshop.com/photoshop_family/topics/classic-cc-uses-90-cpu-during-export?topic-re...

[COBill]

Export performance test on:

• HP Z440 
• Xeon 6-core, 3.6/4 GHz
• 64GB RAM 
• from SSD on a PCIe adapter on the PCIe Bus, Samsung EVO 2TB 
• to SSD on a SATA SSD, Samsung EVO 1TB 
• Quadro K1200 
• 4K monitor

3 tests, exporting 100 raw images to jpeg at 100% quality, 4K resolution, sharpen for screen:

1. 2 min 54.4 sec - edited images 
2. 1 min 33.2 sec - unedited images 
3. 2-3X slowdown for editing concurrent with exporting another 100 unedited images, depending on the task. Library affected more than Develop, occasional flash of the develop window. 

 BTW, it is not a bug when something doesn't work the way we would prefer. 
 

[johnrellis]

There have been a few statements by Adobe employees over the past several years that, after Export was changed in LR 6 / CC 2015 to use multiple cores more effectively, they intended that Export would not consume all of the available CPU, which would allow for interactive use.  I found one of those statements here:
https://feedback.photoshop.com/photoshop_family/topics/lr-cc-2015-2-and-up-cpu-usage-on-export-on-25...

Adobe categorizes a post here as a Problem ("bug" in the vernacular) if LR is not behaving as the developers intended.  It's categorized as an Idea ("feature request") if the current behavior was intended by the developers.

So when LR uses 100% CPU during export, making interactive use very difficult, that's a Problem.

[PhilBurton]

John,  I would characterize this situation as an Issue for users.  I read through some of the comments in that statement you referenced above, and it's clear that people have strong feelings about this situation, but there is real disagreement about if/how to change the current export situation.

I think for most users, they won't care if the issue is called a Problem or Idea.  They just want to get their issue addressed.  That said, the way that software teams work, there might be separate resource allocations between Problems and Ideas.  That also said, Adobe needs to recognize that regardless of what this issue is, it should be a high priority to fix this issue in a way that satisfies most/all people. 

The solution is really not that difficult.  It's just a question of priorities.

Phil Burton

[johnrellis]

Fully agree. 

[Tr0ttsky]

It looks like there are two camps, one that wants Lightroom exports to be super fast and don't care about any slow down. The other camp wants to be able to use Lightroom while exporting and don't mind a slower export.

Seems to me Adobe needs to look at some sort of cpu utilization setting in preferences that can be adjusted by individual users.

[COBill]

Priorities are difficult to set in Unix (MacOS) and Windows (less so than Unix but still not easy) due to the architecture of the operating systems. It can be done but is likely to cause problems with other processes. 
 
Hence the solution normally implemented for a multi-threaded process like Export and Import is to provide a preference for the number of threads that can be utilized by the process. Not ideal, priorities would be a better solution but not until we get an OS with a new internal architecture. MS is working on one that we should see in a couple years. Apple is gradually moving off MacOS to iOS (and variants) for all their products. 
 
In the interim, it "should be" (no guarantees) relatively straightforward to deliver a Preference, MaxThreads=nn. Ideally it could be in the Export dialog so that it could be varied based on other tasks in process. 
 

[johnrellis]

"It looks like there are two camps, one that wants Lightroom exports to be super fast and don't care about any slow down."

...and Adobe has said it was their intention that LR support the second camp.  I don't recall any statements from Adobe saying they would add an option to LR to support the first (but then they rarely indicate ahead of time their intentions with respect to feature requests). 

[PhilBurton]

Without overcomplicating the solution, a thread limitation should be based on the total number of available threads in the system.

[COBill]

A percentage would likely be useful for the most people though I would prefer an absolute number. As I'm not having a problem with Export making my system unusable, perhaps my vote shouldn't count. 
 
While I've not done a scientific study of those who are having problems, they seem to be isolated to Mac users on relatively lightweight systems: all MacBooks and iMacs are lightweight hardware regardless of the Pro label. Windows and Mac Pro users seem to be unaffected though I would expect the problem to be just as serious on a Windows laptop even though Windows is somewhat more efficient at multi-tasking. 

[Tr0ttsky]

I'm experiencing severe slow down on a new i9 Windows machine

[COBill]

Laptop or multi-drive desktop? 

[Tr0ttsky]

Desktop, 32gb ram and Lightroom catalog on dedicated ssd