psensor CPU usage jumps when graph window loses focus

Status changed to 'Confirmed' because the bug affects multiple users.

Thanks for the report, I am also reproducing it.

It is due to the fact that the signal 'draw' is called too often, so psensor is refreshing
too often the curves leading to overusing the cpu.

Unfortunely, the signal 'draw' is not emitted by psensor itself so currently, I don't have any fix.

I can confirm this behaviour as well. (Ubuntu 16.04 AMD64 with stock unity and repository) As soon as Graph window loses focus the CPU power increases (depending on graph window size and amount of plotted data). As soon as focus is regained, processing goes under 1%.
I tested installing version 1.1.3-Ubuntu5, 1.1.3-Ubuntu2 and 0.8.0.3ubuntu3. All leading to the same behaviour.
I could observe this on my desktop with NVIDIA graphics (proprietary driver) as well as on my notebook with Intel graphics N3700.
I am not an expert in programming but it seems to be a problem caused by one of the dependencies used (incorrectly?).
If there is is something to help finding this problem I would be glad to assist.
I really like psensor!

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1582930

Hans-Gregor, thanks for the report.
Currently I know that it is due to the gtk signal 'draw' which is sent by the Gtk layer to psensor.
What I don't know is why the signal is sent. I wonder if it is not Unity. Did you try another window manager?

Hi Jean-Philippe,

I've tested psensor under Xfce (xUbuntu) and indeed psensor behaves has expected. The CPU power stays at virtually 0 in back- and foreground. I tested it installing the xubunut-desktop alongside. After switching back to Unity, psensor still behaved well*. However, as soon as I reactivated the Ambiance-Theme the CPU power used went up again.

*The theme (colors) of unity were (partially) overwritten by the xubuntu-desktop installation. It seems the problem of psensors CPU usage is related to something set by applying the default Unity theme. Something seems to cause the repeated call of the draw function.

You are right it is related to the theme.

The call of the GTK functions: gtk_widget_get_style_context, gtk_style_context_get_background_color, tk_style_context_get_color are emitting a draw signals to psensor when the widget does not have the focus.

BTW, by caching the retrieval of fg/bg colors when drawing the psensor curves, I can easily fix the CPU overuse in the Psensor code. I verified than it works, there is no more CPU overuse when the focus is lost.

I will try to commit a fix in a PPA asap.

Here is the fix: http://wpitchoune.net/gitweb/?p=psensor.git;a=blobdiff;f=src/graph.c;h=60392cc14bbc748e6ce4b739c34ae61fda10494a;hp=792bb258d6679962ccf3904acadd5378030a9f18;hb=c9510a63205885497aa20ddf796cb90efb8c659b;hpb=555a434f8d3119f866eedbe05d9da225bb297b8f

The release 1.1.5 of psensor is containing the fix.

Hans-Gregor, you could use the PPA of psensor to get the fix:

sudo apt-add-repository ppa:jfi/ppa
sudo apt-get update
sudo apt-get install psensor

then restart psensor

Attached the debdiff for Ubuntu Xenial which is fixing the issue

The attachment "lp1582930.debdiff" seems to be a debdiff. The ubuntu-sponsors team has been subscribed to the bug report so that they can review and hopefully sponsor the debdiff. If the attachment isn't a patch, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are member of the ~ubuntu-sponsors, unsubscribe the team.

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Hi,
Jean-Philippe, thank you for the fixed new version! It works well with Unity (Ubuntu 16.04 and default theme) without wasting CPU time. htop reports an average of about 0.6% cpu cycle time running in the background.
Therefore, I can confirm, the binaries provided by ppa:jfi/ppa (Version 1.1.5) fix the bug.

regards Gregor

Thanks for the debdiff Jean-Philippe. Unfortunately it fails to build in Ubuntu 16.04 LTS. I believe you also need to add a second patch:

http://wpitchoune.net/gitweb/?p=psensor.git;a=commit;h=50550d7ed65b9f86b7c231abc993dd858db01c09

Please also tag the patches using DEP-3: (http://dep.debian.net/deps/dep3/)

For example:

Description: Fixed CPU overuse when focus is lost.
Author: Jean-Philippe Orsini <email address hidden>
Origin: upstream, http://wpitchoune.net/gitweb/?p=psensor.git;a=commit;h=9a85d16663d7837698a3b00574a0652db1f849af
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/psensor/+bug/1582930

Thanks!

(unsubscribing sponsors to get it out of the queue until it's good again for review, please subscribe ubuntu-sponsors back once you fixed the issue described in the previous comment)

Second version of the patch (debdiff) adding a fix of a build failure when a recent version of MHD is used.

Marc, thanks for the review and the comment. I am quite lost how to use thse DEP-3 tags in practice, I will try to do it as soon as I understand how to do it:(

Added DEP-3 headers as recommend by Marc

From me it looks like you put the two commits from upstream in the same patch file, while linking only one in the Orig field. Would you please use two different patches? It's even easier, as you'd just be copying the upstream commit.

Given that that fix is in upstream 1.1.5 I marked the bug as fixed already, and kept open only a task for xenial.

unsubscribing sponsors; please re-subscribe it once ready.

It has been well over 12 months now and still the fix version 1.1.5 is *not* in the main repositories for 16.04.

So, simple questions:
Why not?, and
Why is to so?