Hello,

yesterday I noticed that copying multiple small files (~13k .png icons) takes way too much time. I tried digging deeper and comparing with other file managers and ended up doing the following test:

System:

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 Arch x86_64 | linux-ck-bobcat | Zotac AD02 | AMD Zacate e-350@1,2GHz | Radeon 6310 | 4GB RAM

Setup:

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copy 13k icons ext4 SSD -> ext4 HDD, destination folder deleted between runs. Each file manager tested 3 times

Results:

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dolphin: 1:23
thunar: 1:17
nautilus: 0:26
pcmanfm: 0:10
command line: 0:02

What I noticed is that there were a few kio-file processes that made the CPU peak at 100% throughout the whole process. Baloo/Akonadi were disabled for the test, but they didn't produce any CPU usage when they were on anyway. There is definitely room for optimization here. I'd post that into the brainstorm section, but I have no suggestions on what to improve. Maybe use a (larger) buffer when copying? Optionally allowing the user to specify the size.

I've tested copying the same folder on win8.1, and this is how windows explorer compares:

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dolphin: 1:23
thunar: 1:17
nautilus: 0:26
explorer: 0:14
pcmanfm: 0:10
command line: 0:02

There should definitely be some optimization done to the way file operations are done.

Thanks for sharing your test results. Optimizations in this area would be welcome indeed.

All file operations in Dolphin and other KDE applications are done by the KIO framework: http://quickgit.kde.org/?p=kio.git

Anyone who is interested in working on optimizations should analyze what KIO does inefficiently, and try to find ways to improve it. The Frameworks development mailing list is probably the best place to discuss ideas how the KIO code can be improved: https://mail.kde.org/mailman/listinfo/k ... orks-devel

Interesting comparison! I've noticed KIO transfers are slow from local to network attached storage and to usb flash storage. I've probably not noticed other general slowness because I do most of my large transfers using rsync. I might start using pcmanfm after doing some of my own testing!