Review Request: Implemented multithreading in KFileItemModelSortAlgorithm

[Frank Reininghaus]

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Thanks for the new patch! 

I'm afraid it's a lot more complex than it needs to be. A recursive implementation like the one I suggested in
https://bugs.kde.org/show_bug.cgi?id=306290#c17 would be much simpler (and not that much different from the 2-thread solution you've posted earlier):

a) No need for your data structure ThreadList.
b) No loops.
c) No need to add complex code for parallel merging - you'd get that for free.

Maybe the reason for the rather insignificant performance increase is hidden somewhere in this complexity, I can't really say at first sight.

I don't know if you're still motivated to continue working on this, but I would very much prefer a straightforward recursive solution :-) 


- Frank Reininghaus


On Oct. 25, 2012, 11:48 a.m., Emmanuel Pescosta wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> http://git.reviewboard.kde.org/r/107025/
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> (Updated Oct. 25, 2012, 11:48 a.m.)
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> 
> Review request for Dolphin and Frank Reininghaus.
> 
> 
> Description
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> Implemented multithreading in KFileItemModelSortAlgorithm.
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> If more than 100 items to sort and ideal thread count is greater than 1 -> sort them with parallelSort (2 Threads)
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> Use maximal 2 Threads, because more than 2 Threads are "slower" (more overhead than speed up). (I also have a patch which uses n Threads for sorting, if you want test it ;)
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> 
> Diffs
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>   dolphin/src/kitemviews/private/kfileitemmodelsortalgorithm.h 3a596df 
>   dolphin/src/kitemviews/private/kfileitemmodelsortalgorithm.cpp e0aac13 
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> Diff: http://git.reviewboard.kde.org/r/107025/diff/
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> Testing
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> About 2 seconds faster with sorting 500.000 files.
> About 5 seconds faster with sorting 1.000.000 files.
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> 
> Thanks,
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> Emmanuel Pescosta
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>

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