Re: Disk access *every* 5 seconds?
Hi,
On Tuesday 27 November 2001 19:04, Udo Burghardt wrote:
> Hello list,
>
> keeping uptodate with testing I am running KDE 2.2 since it is
> available without Problems. Thanks Ivan!
>
> My last update was yesterday. And now I have a periodical access to one
> harddisk (/usr) _exactly_ every 5 seconds. One can hear the heads
> moving two times with a delay of less than one second. This cycle
> repeats precisely every five seconds. Running xosview I can see the
> SCSI-Interrupt flashing once and the DISK activity states 69K for this
> cycle of measurement.
It might be kded. There are two things which are checked by kded every 5
seconds (found by grepping for 5000 in the kdelibs sources). It is checking
files on remote filesystems every 5 seconds. I believe that this isn't
causing of the disk activity, since the checking of files on local
filesystems which happens every 0.5 seconds, and isn't causing disk activity
either. The second thing that's checked is the hostname. This is done using
gethostname. I don't know if this could cause the disk activity. You could
try to change the value of HostnamePollInterval in kderc, and see if the
interval of the disk access is changed by this (see README.kded for more
information).
> [..]
Greetings,
Wilco
Welcome to this readme about KDED.
KDED stands for KDE Daemon which isn't very descriptive.
KDED runs in the background and performs a number of small tasks.
Some of these tasks are build in, others are started on demand.
Build in tasks
==============
*) Checking for newly installed software and updating ksycoca when new
software is detected. Updating of ksycoca is done by the program kbuildsycoca
which gets started by kded. When kded is first started it always runs
kbuildsycoca to ensure that ksycoca is up to date.
*) Checking for newly installed update files. Applications can install
*.upd update files. These *.upd files are used to update configuration files
of users, primarily when new versions of applications are installed with
(slightly) different configuration file formats. Updating of configuration
files is done by kconf_update. kded starts kconf_update when it detects a
new update file. When kded is first started it always runs kconf_update to
ensure that it has not missed any update files. kconf_update keeps track
of which update files have been processed already in the config-file
kconf_updaterc. It only performs a certain update once.
*) Checking for hostname changes. It is a really bad idea to change the
hostname of a running system and it usually only happens with incorrectly
configured dial-up connections. Never the less, kded will check for hostname
changes and if it detects one it will make the necassery changes to the
KDE environemnt and X-server to allow continued proper operation. The
program kdontchangethehostname is executed to make the actual changes.
Configuration of build in tasks.
================================
The build in tasks have some configuration options that can be changed by
editing the kdedrc configuration file. Changes need to be made with a text-
editor, there is no GUI available. All options are listed under the [General]
group:
PollInterval: This can be used to adjust the time interval at which the local
filesystem is checked for new software or update files. The time is specified
in milliseconds and has a default of 500 (0.5 seconds).
NFSPollInterval: This can be used to adjust the time interval at which remote
filesystems, such as NFS or Samba, are ebing checked for new software or
update files. The time is specified in milliseconds and has a default of 5000
(5 seconds).
The above options are not used when FAM is used to watch for changes in the
filesystem. Specifying larger intervals may reduce the CPU load and/or
network traffic. Shorter intervals are not recommended.
HostnamePollInterval: This can be used to adjust the time interval at which
the hostname is checked for changes. The time is specified in milliseconds
and has a default of 5000 (5 seconds).
CheckSycoca: This option can be used to disable checking for new software.
ksycoca will still be build when kded starts up and when applications
explicitly request for a rebuild of the ksycoca database. The user can
also manually rebuild ksycoca by running the kbuildsycoca program.
The default value of this option is "true". Checking can be disabled by
setting this option to "false".
CheckUpdates: This option can be used to disable checking for update files.
kconf_update will still be run when kded starts up.
The default value of this option is "true". Checking can be disabled by
setting this option to "false".
CheckHostname: This option can be used to disable checking for hostname
changes. The default value of this option is "true". Checking can be
disabled by setting this option to "false".
Example kdedrc file with default values:
[General]
PollInterval=500
NFSPollInterval=5000
HostnamePollInterval=5000
CheckSycoca=true
CheckUpdates=true
CheckHostname=true
Tasks loaded on demand
======================
Some things can be greatly simplified if they can be coordinated from a
central place. KDED has support for modules that will be demand-loaded
whenever an application attempts to make DCOP call to the module.
This can be usefull for central administration tasks.
An example of a KDED module is the print module. When an application prints
a file, the print module will watch over the print-job while the file
is being printed. This allows you to close the application after submitting
your print-command to the printer, the print module will make sure to
inform the user when a print problem occurs (printer out of paper, printer
on fire)
A KDED module should install a .desktop file with
ServicesTypes=KDEDModule
A KDED module will be loaded on startup if it has a line
X-KDE-Kded-autoload=true
Normally KDED modules are loaded whenever they are accessed. On demand loading can
be disabled by putting the following line in the .desktop file:
X-KDE-Kded-load-on-demand=false
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