Adobe Lightroom Parallel Processing Speeds Up JPEG Export by 50%

Started Mar 5, 2013 | Discussions thread
AxelR
Senior MemberPosts: 1,041
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Re: Adobe Lightroom Parallel Processing Speeds Up JPEG Export by 50%
In reply to Jan_Shim, Mar 6, 2013

Jan_Shim wrote:

I don't use LR on a regular basis and don't know the inner workings of the software to comment about how well LR scales or not scale. My test simply demonstrated its the performance gains using its 'parallel processing' capability to save time instead of just a straight batch export.

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JAN SHIM
Professional freelance photographer
http://www.shimworld.com | ttp://www.facebook.com/janshimphoto

Well, the arithmetic is pretty straightforward: 2x CPU power for a CPU-bound process = half the processing time. 4x CPU power = 1/4 the processing time, etc, until some bottleneck start to become predominant, which seems to be already the case here as your batch only ran twice as fast with 4x the CPU power (and 4x the power consumption), an indicator of poor scalability knowing that image processing is a CPU-bound task for the most part, until disk throughput becomes an issue as the level of parallelism increases (number of images processed concurrently).

Your SSD disks can probably read about 10 raw images per second and write some 20 JPEGs per second, so disk should not be a bottleneck on your very fast machine with 4 cores at work, in other words, throwing 4 times the workforce at this type of problem should get you close to a 4 times increase in throughput and you only got two times.

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