Hi Albert,
I am mostly a user of KDEPIM, but since I experienced quite some performance
issues and did some analysis and reports every now and then, I thought I share
my findings.
Am Samstag, 5. April 2014, 16:40:24 schrieb Albert Astals Cid:
** Please CC me and r-t list, i'm not subscribed to pim list. **
Hello guys, as I hope you all know this Wednesday we are supposed to tag the
final release for 4.13.
I am sending this email to ask for opinions on the value of adding an extra
RC and delaying the 4.13.0 release for at least a week.
I'm going to explain why I'd like this to happen.
Since the update to 4.13 Beta I've been having lots of CPU and I/O problems
in pim related stuff, most notably akonadi_baloo_indexer,
akonadi_maildir_resource friends.
On every release i've complained on IRC to be told oh yes, we just fixed
this thing and will be available on the next release.
But here I am, using 4.13 RC and with even KMail closed
mysqld+akonadiserver+akonadi_maildir_resource are using 100% of one of my
CPU cores and writing/reading around 10MB/s to my slow disks.
So you are using a POP3 setup? Or how is the maildir resource filled on your
setup? How big is it?
I reported several bugs regarding slowness of maildir resource with lots of
folders with lots of mails in it, including a report of
akonadi_maildir_resource hogging up one Intel Sandybridge core on a Dual SSD
BTRFS RAID 1 setup for several minutes after filtering about 100 mails into
their folders[1]. And one for MySQL tuning, but at least from my observation
the issue isn´t MySQL here, I thought so first, but I am not convinced after a
deeper look at show innodb engine in MySQL is doing. See recent thread in pim-
ml as well[3]. I am keen to look at it some more, but after spending quite a
lot of time on analysing I needed a break. Well some other things Mark
found[4]
But on the other hand my setup might be considered extreme. About 100 folders,
quite some of them with several ten thousand mails and one (kernel-ml) with
about 22 unread mails.
It is my impression that both for my private POP3 setup and my work IMAP setup
performance got way better on the upgrade from Akonadi 1.11.0 to Akonadi
1.12.0. Still I see the akonadi_maildir_resource hogging a core for minutes at
times. But it doesn´t seem to happen after every mail retrieval / mail
filtering cycle. Sometimes MySQL chimes in using something between one and
three cores, but I see akonadi_maildir_resource for minutes on 100% CPU
without any notable CPU activity of mysqld as well.
But when it does, I see it synchronizing folders. In strace I see it getting
dentries and checking the existance of every little file.
I don´t know whether another week will lead to a fix. I got the impression that
performance issues with Akonadi are not yet fully understood.
In my eyes there are two things which contribute a lot to KMail being
basically unusable for times of several minutes:
1) Maildir resource synchronizes folders needlessly. Not sure what triggers it
tough.
2) Akonadi blocks out KMail almost completely when maildir resource is doing
so. To me Akonadi appears to be basically single threaded. While I understand
one of its design goals of Akonadi were that GUI applications like KMail never
block again.
Also remember for me this is Akonadi 1.12.0 and KDEPIM 4.12.4 still. But for
these versions, although I see improvements, I still think KDEPIM + Akonadi
needs serious performance related work. Cause I just don´t get how filtering
100-200 mails to their folders can lead to a usage of one Sandybridge core for
minutes unless I assume somewhere something does unnecessary work. Its not a
I/O bottleneck according to atop.
That said:
- I don´t think the performance issues are new. So they are no regression. Or
did you found it regressing recently?
- I am not sure whether another week would help with fixing them, as… my bet
is: If the cause is understood someone likely would have fixed them already.
I do think the KDEPIM / Akonadi team needs helping hands. I tried to help a
bit, but I didn´t come around at looking at the code and when I do I first need
to understand some of it before I can consider proposing a patch. :)
[1] [Akonadi] [Bug 332684] New: [Maildir] lots of stats calls to
/etc/localtime on synchronizing folders
= can be work-arounded by setting TZ env var, yet folder synchronization
still is slow.
[2] [Akonadi] [Bug 332626] MySQL tuning: adaption of MySQL tuning options for
larger accounts
[3] [Kde-pim] Akonadi MySQL backend: tuning for larger accounts or switching
to MariaDB with a different storage engine?
[4] PIM Sprint, Calendar progress and Akonadi
Datum:Donnerstag 17:13
Autor:Mark Gaiser (markg)
http://kdeblog.mageprojects.com/2014/04/03/pim-sprint-calendar-progress-and-akonadi/
[5] Re: [Kde-pim] Akonadi MySQL backend: tuning for larger accounts or
switching to MariaDB with a…
This is not the
