Bug 264278

Summary:	KMail uses too much CPU time reacting to Akonadi synchronising IMAP folders
Product:	[Applications] kmail2	Reporter:	Thiago Macieira <thiago>
Component:	general	Assignee:	kdepim bugs <kdepim-bugs>
Status:	RESOLVED UNMAINTAINED
Severity:	major	CC:	anmeldungen, bartotten, ibrahim, markotahal, Martin, meyerm, neikokz+kbugs, p.heinlein, winter
Priority:	NOR
Version:	2.0.89
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Thiago Macieira 2011-01-25 18:40:33 UTC

Version:           2.0.89 (using Devel) 
OS:                Linux

When Akonadi is synchronising its IMAP folders, KMail / Kontact's CPU usage goes to 100% and it becomes sluggish. It doesn't reach unresponsiveness state, but it's slow enough reacting to user interaction that it's unusable.

This is being run on a Quad-Core Core-i7 @ 2.67 GHz, 2 threads per core. It's not a limit of the system, since most other CPUs are idling -- just one is at 100% usage, by the kmail / kontact process.

Depending on the number of folders and the connection speed, the period under which KMail is unusable can be quite long. And if the connection speed is high, the level of usability decreases (that is, KMail is doing more work and reacting less to user interaction).

In my case, I had one IMAP server with 50+ folders at a 5-minute check interval. That means KMail would be completely unusable about 1 every 5 minutes.

Reproducible: Always




OS: Linux (i686) release 2.6.36.2-server-1mnb
Compiler: gcc

Comment 1 Allen Winter 2011-04-11 16:09:31 UTC

adding as a showstopper

Comment 2 Peer Heinlein 2011-05-16 23:09:10 UTC

I can confirm that exactly. (OpenSUSE 11.4)

There are lots of reports like that. It looks like this is REALLY a problem. Who can fix that?

Comment 3 Mark 2011-06-11 11:05:20 UTC

same here, kde 4.6.4, archlinux, atom cpu. 
mysqld and akonadi_resource produce high cpu load (up to 80%)

Comment 4 Jan 2011-07-31 07:43:40 UTC

Same on my notebook running KDEPIM 4.7. Akonadi is using 100% CPU (both cores) on synchronizing my disconnected IMAP resource

Comment 5 Jan 2011-08-02 08:44:14 UTC

Maybe related to http://blogs.kde.org/node/4457

Comment 6 David Martí 2011-08-04 12:38:49 UTC

Same here, I really hope this gets fixed ASAP, as it's a showstopper.

KDE 4.7.0 Arch Linux

Comment 7 BartOtten 2011-10-04 19:54:05 UTC

4.7.1 syncing Gmail,14k emails, multicore processor, Nepomuk enabled, for over an hour now, disabled interval

Ouput of top 
17385 bart      20   0  228m  29m 6676 S    151  0.8  25:07.96 akonadiserver                                                                     17393 bart      20   0  296m  23m  18m S      9  0.6   0:52.77 akonadi_maildis                                                                   17043 root      20   0  415m 159m  95m S      8  4.0   3:44.67 Xorg  

Very much IO-activity. While writing that stops but Akonadi still consumes 88%

Comment 8 Martin Steigerwald 2015-04-12 12:49:37 UTC

Dear Thiago, thank your for reporting the bug. Also thank you to anyone who confirmed it. The bug is related to an ancient version of both KMail and (thus) Akonadi which still use Nepomuk.

As I do not see any such issues anymore even with a huge IMAP account and as I do not see any confirmation of it with KMail from KDEPIM 4.14 I am thus closing this bug as resolved/unmaintained. If you still see this issue with KMail from KDEPIM 4.14 and Akonadi 1.13 please comment and reopen the bug. If you can´t reopen it, tell me, and I will do it. Please in that case, if you can try with latest KDEPIM 4.14 and Akonadi 1.13 compiled from the respective git branches. At least for Akonadi 1.13 as it received notable MySQL related performance fixes recently. Thanks, Martin