[Bug 211416] Optimise kde performance on nfs

[Dean Montogmery]

https://bugs.kde.org/show_bug.cgi?id=211416


Dean Montogmery <dmonty at sd73.bc.ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dmonty at sd73.bc.ca




--- Comment #2 from Dean Montogmery <dmonty sd73 bc ca>  2010-06-02 21:53:26 ---
I'm experiencing the same problem with our diskless workstations running kde
4.4.2 over nfs.  Tested kde 4.4.2 for both diskless Kubuntu diskless Arch.

* No difference when switching between nfs3 and nfs4 mounts.
* It is really slow logging in (50 seconds)... and the interface is slow as
well.
* KDE 3.5 is definitely faster over nfs.

Here are some things to note:

Running KDE 3.5 on diskless does not have the same slow issues logging in. 
Except the K menu was slow loading.  I attached an strace to it and found that
it was scanning thousands of directories to find the 16x16 menu icons.  The
strace showed hundreds of "No such file or directory" as kde searches for
icons.  I was able to fix the slow menu by creating an icon theme and
pre-loading it with all the required 16x16 icons <== I wrote a script for that.
 Once all the 16x16 icons were available the menu was instant in loading.

In a nutshell NFS is very poor/slow when software scans for files that don't
exist.  KDE uses the scan folder trick to hunt for and find themes, etc.

---
Because the menu fix was successful I attached a strace to kdm for the login
process of kde 4.4.2 and and discovered that there were 46,372 "No such file or
directory" scans.

===
Possible ideas/solutions:

* instead of using the file system as a database to locate/lookup files -
somehow create a cache file that can be quickly scanned by kde to find the
files it needs.

* have nfs do some sort of client-side caching of the directory structure to
reduce the overhead of looking for files that do not exist.

** My guess is that the nfs guys will blame kde, and the kde guys will blame
nfs.

PS our school district is currently running thousands of diskless workstations
running kde 3.5.  I would like to upgrade them to kde4 however the slow
kde4+nfs issues may force us to switch to another desktop environment.

-- 
Configure bugmail: https://bugs.kde.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.