[Kroupware] Some speed issue debunking

[Bo Thorsen]

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Hi all,

I have heard some strange issues with speed. So I tried testing it myself. 

I have thirteen IMAP folders laid out as so:

max
  Inbox
    Calendar
    Contacts
    Tasks
    Notes
    Outbox
    Sent-mail
  user
    bo-shared
      Calendar
      Contacts
      Tasks
      Notes

Of these folders, the ones in user are all shared, with user being a 
subfolder only folder. My groupware folders are currently under Inbox, 
but I sometimes also use the folders under bo-shared for testing. The 
folders have between 1 and 15 mails in them currently. The client is 
current cvs status (which is more or less equal to the upcoming RC3 - in 
which no speed fixes have been applied).

The server is max.kde.org - i.e. not a local one but one located somewhere 
in Germany. I'm located in Denmark with a 2mbit line just for me. I don't 
know what is currently installed on max - probably something newer than 
RC1 of the server. Martin, Tassilo - please correct me if I'm wrong. My 
client machine is a dual Athlon 2000 with 1GB memory. I don't know what 
the server machine is.

Then numbers in my simple test:

A sync on this with noting changed, takes 7-8 seconds. Just over half a 
second per folder.

I now added a single mail to each of the folders (user exepted, since this 
can't hold mails). Syncing this took 14 seconds.

Then I removed that single mail from each of these folders again, and now 
a sync took 11 seconds.

End of numbers.

I'm having trouble seeing the speed issues that have been reported. I do 
know, however, that uploading mails is slow. The reason for this is 
stability - we simply only upload a single mail and wait for the 
succesful return before going to the next. The reason for this is that 
the mail must be deleted locally and we wanted to be sure never to loose 
a mail over this.

I know this is nowhere near a real test. For that I would need different 
layout structures of the tree and a LOT more mails in each folder. My 
hope is that my numbers here will give reason for some more specific 
reports than just "IMAP is slow". So please fire up your tests and send 
your numbers, if you have better tests that show some deficiencies (the 
slow upload not included - I will probably refuse to fix that anyway). 
But please: If you can't get anywhere near the numbers I've given here 
with setups resembling it, don't send it as a speed report, but as a 
question on why your setup doesn't perform well. Unless your machine is 
much slower than mine, because then it could show that the client sync 
speed depends on the client machine speed, which would be really bad. 
There might also be other reasons that I haven't thought of, so if you're 
in doubt, send it anyway.

It looks like there are people working on the IMAP layer in KDE for 3.2 or 
perhaps 3.3, and it could be that there will be some speed improvements 
from that work. But IMHO, KMail should receive a real IMAP implementation 
instead of using the KDE IO layer for it. But this would be several man 
months to get right, and I doubt it will happen unless some company 
decides to sponsor that development. KIO really is suboptimal for IMAP, 
but it is a working implementation that we have available now.

Bo.

- -- 

     Bo Thorsen                 |   Praestevejen 4
     Senior Software Engineer   |   5290 Marslev
     Klarälvdalens Datakonsult  |   Denmark
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