Bug 346363

Summary: Uses more than one CPU core while scan for new items
Product: [Applications] digikam Reporter: Axel Krebs <axel.krebs>
Component: Database-ScanAssignee: Digikam Developers <digikam-bugs-null>
Status: REPORTED ---    
Severity: wishlist CC: caulier.gilles, mohammed.ahmed.anwer
Priority: NOR    
Version First Reported In: 4.9.0   
Target Milestone: ---   
Platform: Ubuntu   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Pic s showing only ONE CPU is used :-( !!
additional pic showing 25% = 1/4 of four CPUs

Description Axel Krebs 2015-04-19 15:10:12 UTC 
If I start servicing my databases, I experience always very slow progress. 
"Servicing" about 900 new pics takes time for hours and hours seemingly not to end up at alll :-(

In this case, I just seacrh for new pics and refresh previews.

My motherborad runs an powerful quadcore.
When checking put for reasoins, I found, that didiKam just engages 25% of my CPU(s). 
For this reason, I conclude, that digiKam doe _not_ use all CPUs right now.

This is a severe handycap, as it make digiKam appear slowly.

 

Reproducible: Always

Steps to Reproduce:
1. Please take care, that digiKam runs all CPU a machine provides and/or introduce an intelligent CPU management, a user can pre-select about the number of engaged CPUs.
2.
3.

Actual Results:  
digiKams performance is not satisfying at all: maybe you'll check ourt GIMP concerning this feature or HUGIN, which applyies graphic-card-capabilities.

Expected Results:  
digiKam should work and run on the level of nowadays programs. 
It seems to be old fashioned to just use one single CPU.

Because of the slowliness, whicgh forces the user to wait terribly long, this is a failure of major importance!!!
Comment 1 Axel Krebs 2015-04-19 15:14:00 UTC 
Created attachment 92118 [details]
Pic s showing only ONE CPU is used :-( !!
Comment 2 Axel Krebs 2015-04-19 15:14:48 UTC 
Created attachment 92119 [details]
additional pic showing 25% = 1/4 of four CPUs
Comment 3 caulier.gilles 2015-04-19 21:04:42 UTC 
Mohamed,

Another bugzilla entry relevant of your future GSoC 2015 project...

https://community.kde.org/GSoC/2015/Ideas#Project:_Re-write_database_KIO-slaves_as_pure_Qt5_using_multithreading

Gilles Caulier
Comment 4 caulier.gilles 2016-08-06 13:50:57 UTC 
See bug #329091.

Exiv2 shared library sound have problem while the library is called from multi-threads running in multi-core cpu.

For the moment, we have disabled the multi-core cpu in maintenance tools which use Exiv2 shared library. This include scan for new items and metadata synchroniser.

Gilles Caulier