P: Make use of extra cores to process multiple photos in parallel

Spring Feng wrote, "The overall export speed is NOT increased based on my unscientific testing.. although LR is now using the full CPU threads, but for some funny reason, the per photo exporting speed dropped a lot and seems totally killed the effort of utilizing multiple cores..."

My perception was different, so I did a small experiment on my 4-core MacBook Pro, exporting 20 raw files as quality-60 JPEGs. CC 2015.1.1 was 1.41x (41%) faster than LR 5.7.1. Total CPU utilization increased by 1.51x, from 53% to 80%. (LR probably shouldn't use more than 80%, to ensure reasonable interactive response during the export.) This kind of speedup from using multiple processors is pretty good and what I would have expected.

A couple of import things to note:

- Versions of LR prior to CC 2015.1.1 / 6.1.1 had a serious bug in export, often causing it to do significantly more work than necessary. So if you're on such an earlier version, consider upgrading (but to 2015.1.1, not 2015.2.1!).

- The progress bar in the upper-left corner is updated much more frequently in LR 5.7.1 than CC 2015.1.1, giving the impression that LR 5.7.1 is much zippier. LR 5.7.1 updates it after each file is exported, and it shows the filename; whereas CC 2015.1.1 updates it only 8 times (after 12.5% of the total work is done), and it doesn't show filenames.

Details of the experiment:

- MacBook Pro (late 2013), Core i7, 2.6 GHz, 4 cores/8 logical processors, L2 256 KB/core, L3 6 MB, 16 GB memory, 1600 MHz DDR3, SSD.

- The raw files were 5472 x 3648 .arw's, 21 MB, with all the basic settings adjusted, sharpening, and one stroke of the local adjustment brush.

- The JPEGs were exported the original size, quality 60, and were 3.9 MB.

"The whole UI is not responding when the export is taking progress.. "

Please add your vote and opinion about this to this topic: http://feedback.photoshop.com/photosh...

I am glad that after 3 years this thread is still alive...

Yes, Adobe has finally addressed this issue with latest CC/6 updates... although is poorly implemented in my opinion.

1. The whole UI is not responding when the export is taking progress.. I don't mind lightroom taking all resources when exporting (i.e. other programs could run slowly when exporting is happening), but freeze its own UI doesn't make sense.
2. The overall export speed is NOT increased based on my unscientific testing.. although LR is now using the full CPU threads, but for some funny reason, the per photo exporting speed dropped a lot and seems totally killed the effort of utilizing multiple cores...

Thanks for the info. I have LR6 but I was just curious how punish my 6 cores to maximum. Glad to hear that LR6 utilizes all cores better and external script is not necessary.

Unfortunately, Rob Cole hasn't been heard from since January 2015, and his site went offline soon after. (Hope everything is ok...)

With respect to his script, note that LR CC 2015 / 6 now fully utilizes multiple processors for export, so the script is unnecessary. In fact, some people now complain that LR is too aggressive in using multiple processors for export, to the point that interactive use is impossible while an export is in progress.

Link is not working

It happens automatically in 6 - you don't do anything. You can't do it in 5 without a plug-in or setting it up manually (e.g. select some, set them exporting, select some more, set them exporting at the same time)

Could you tell me how its done please? I have 5.7. Many thanks

Lightroom CC/6 now does this automatically

The author's Web site, robcole.com, has been down for many weeks. Not clear if it's coming back, which would be too bad.