[kde-freebsd] QFilesSystemWatcher instead of polling/FAM

[Kris Moore]

On 06/25/2010 17:15, Tijl Coosemans wrote:
> On Friday 25 June 2010 19:41:11 Kris Moore wrote:
>    
>> On 06/25/2010 12:37, Tijl Coosemans wrote:
>>      
>>> KDE currently uses polling to detect file and directory changes on
>>> FreeBSD, which can use up cpu time (and laptop battery power). The
>>> kded4 process seems to make heavy use of this and currently
>>> continuously consumes about 5% of my cpu and often causes it to be
>>> throttled up by powerd.
>>>
>>> I've attached a patch that makes KDE use QFileSystemWatcher on
>>> FreeBSD which uses kqueue instead of stat. I've been using it for
>>> the past few days and it seems to work rather well.
>>>
>>> One thing I'm not sure about is whether it works with NFS, so it
>>> could use some more testing. If you'd like to test it, replace
>>> /usr/ports/x11/kdelibs4/files/patch-kio-kio-kdirwatch.cpp with the
>>> attached patch and reinstall kdelibs.
>>>        
>> Just built with this patch here. It does greatly improve my kdeinit4
>> processes, went from a constant 8-10% to 0-1%.
>>
>> However, it does mess up NFS. When browsing my NFS mounts it doesn't
>> show any directory/file changes until I manually refresh the view.
>> Is this something fixable?
>>      
> It can be fixed in Qt or in KDE. Both already provide polling as a
> fallback and it would be easy to add some logic similar to what
> devel/gamin does (call statfs(2) on the given path and use kqueue when
> MNT_LOCAL is set, polling otherwise).
>
> For now, you can also add the following to your ~/.kderc:
>
> [DirWatch]
> nfsPreferredMethod=Stat
>    

Great, that seems to work. I was also able to add it to 
/usr/local/kde4/share/config/kdeglobals and it seems to take effect as 
well. This is such a reduction in CPU usage that this patch really 
should be enabled by default :)

-- 
Kris Moore
PC-BSD Software
iXsystems