Review Request: Implemented multithreading in KFileItemModelSortAlgorithm

[Emmanuel Pescosta]

On Oct. 25, 2012, 5:53 p.m., Emmanuel Pescosta wrote:
> > I also like to ask to postpone merging this feature for now! Not for long, just one or two weeks. I really like to implement the suggestion of Christoph Feck from the KFM-Devel mailing list (in the thread: "Ideas for improving sorting. Goal: under 1 second for 200.000 files."). That might speed up the sorting massively and make multithreading it completely pointless. Why pointless? Well, if the sorting operation can be done under a second for such huge folders then i doubt multithreading is going to speed it up much more.
> > 
> > Again, this is - at this moment - just an idea on the list which i'm trying to implement right now.

> Why pointless? Well, if the sorting operation can be done under a second for such huge folders then i doubt multithreading is going to speed it up much more.

I think multi-threading is also good for busy systems. 

For example:

| Core 1 | Core 2 |
|  75 %  |  80 %  |

-> Single-Threading: Dolphin has 25% of Core 1 OR 20% of Core 2 for sorting
-> Multi-Threading: Dolphin has 25% of Core 1 AND 20% of Core 2 for sorting (In theory ;)


- Emmanuel


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On Oct. 25, 2012, 7:42 p.m., Emmanuel Pescosta wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://git.reviewboard.kde.org/r/107025/
> -----------------------------------------------------------
> 
> (Updated Oct. 25, 2012, 7:42 p.m.)
> 
> 
> Review request for Dolphin and Frank Reininghaus.
> 
> 
> Description
> -------
> 
> Implemented multithreading in KFileItemModelSortAlgorithm.
> 
> If more than 100 items to sort and ideal thread count is greater than 1 -> sort them with parallelSort (2 Threads)
> 
> 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 ;)
> 
> 
> Diffs
> -----
> 
>   dolphin/src/kitemviews/private/kfileitemmodelsortalgorithm.h 3a596df 
>   dolphin/src/kitemviews/private/kfileitemmodelsortalgorithm.cpp e0aac13 
> 
> Diff: http://git.reviewboard.kde.org/r/107025/diff/
> 
> 
> Testing
> -------
> 
> About 2 seconds faster with sorting 500.000 files.
> About 5 seconds faster with sorting 1.000.000 files.
> 
> 
> Thanks,
> 
> Emmanuel Pescosta
> 
>

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