synchronize gnome applets update interval?

[Alex Murray]

On Wed 28 Mar 2012 15:17:14 CST, Németh Márton wrote:
> Hi Aley, Carlos, Martin, Todd, Benoît and Davyd,
>
> I'm using your gnome applets to monitor the following things on my laptop:
>   - CPU temperature (sensors-applet, http://sensors-applet.sourceforge.net/ )
>   - CPU usage (multiload-applet-2)
>   - CPU frequency (cpufreq-applet)
>
> My primary goal is to keep the CPU fan quiet as far as possible. This can
> be achieved if the CPU temperature is kept low which depends on the CPU
> usage and on CPU frequency.
>
> Then I run powertop 1.13 ( http://www.lesswatts.org/projects/powertop/ )
> to see what processes are causing wakeups. I realized that the applets I
> run in order to have an overview on the CPU usage causes additional CPU wakeups.
>
> So I modified the refresh interval of sensors-applet to 5.0s.
> The cpufreq-applet does not have any possibility to reduce the update interval.
> I also modified the default update interval of multiload-applet-2 to 5000ms.
>
> As you can see I can set up two of the applets to wake up the CPU once in
> 5 seconds, but these two alone will wake up the CPU worst case every 2.5 seconds.
>
> I don't know if there is any possibility to synchronize the gnome applets
> so that they wakes up one after the other causing only one wakeup every 5 seconds.
>
> Here is the list of software versions I used:
>
> $ lsb_release -a
> LSB Version:
> core-2.0-ia32:core-2.0-noarch:core-3.0-ia32:core-3.0-noarch:core-3.1-ia32:core-3.1-noarch:core-3.2-ia32:core-3.2-noarch:cxx-3.0-ia32:cxx-3.0-noarch:cxx-3.1-ia32:cxx-3.1-noarch:cxx-3.2-ia32:cxx-3.2-noarch:desktop-3.1-ia32:desktop-3.1-noarch:desktop-3.2-ia32:desktop-3.2-noarch:graphics-2.0-ia32:graphics-2.0-noarch:graphics-3.0-ia32:graphics-3.0-noarch:graphics-3.1-ia32:graphics-3.1-noarch:graphics-3.2-ia32:graphics-3.2-noarch:qt4-3.1-ia32:qt4-3.1-noarch
> Distributor ID: Debian
> Description:    Debian GNU/Linux 6.0.4 (squeeze)
> Release:        6.0.4
> Codename:       squeeze
> $ dpkg -l gnome-power-manager gnome-applets sensors-applet
> Desired=Unknown/Install/Remove/Purge/Hold
> | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
> |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
> ||/ Name                             Version                          Description
> +++-================================-================================-================================================================================
> ii  gnome-applets                    2.30.0-3                         Various applets for the GNOME panel - binary files
> ii  gnome-power-manager              2.32.0-2                         power management tool for the GNOME desktop
> ii  sensors-applet                   2.2.5-4                          Display readings from hardware sensors in your Gnome panel
>
> Regards,
>
> 	Márton Németh
>

Hi Márton,

Thankfully you needn't worry too much about unsynchronised wakeups 
since the glib developers already thought of this and there exists the 
function g_timeout_add_seconds() [1] which causes the wakeups to occur 
in whole second amounts AT whole second intervals - so multiple wakeups 
are synchronised for exactly the reason you want.

sensors-applet already uses this [2] as does cpufreq [3] however it 
looks like multiload doesn't [4] - but a simple patch to change this to 
the seconds variant shouldn't be too hard and should then allow all 3 
to be in sync (as far as I can tell).

Cheers
Alex

[1] 
http://developer.gnome.org/glib/2.30/glib-The-Main-Event-Loop.html#g-timeout-add-seconds-full
[2] 
http://sensors-applet.git.sourceforge.net/git/gitweb.cgi?p=sensors-applet/sensors-applet;a=blob;f=sensors-applet/sensors-applet.c;h=e9801a05f2be8631c2bfa59ed299e338a7be57c5;hb=HEAD#l1415
[3] 
http://git.gnome.org/browse/gnome-applets/tree/cpufreq/src/cpufreq-monitor.c#n319
[4] 
http://git.gnome.org/browse/gnome-applets/tree/multiload/load-graph.c#n377