Another thing to try: do all of the looping, image loading etc. in the background process, but queue the actual change of the background image as a deferred action (#addDeferredUIMessage:). ________________________________________ From: pharo-project-bounces@lists.gforge.inria.fr [pharo-project-bounces@lists.gforge.inria.fr] On Behalf Of Stéphane Ducasse [stephane.ducasse@inria.fr] Sent: Tuesday, December 14, 2010 1:56 PM To: Pharo-project@lists.gforge.inria.fr Subject: Re: [Pharo-project] Background changer script kills Pharo thanks We will have to have alook at semaphore and other.... stef On Dec 14, 2010, at 7:08 PM, Tony Fleig wrote:
In case anybody is interested in this...
I added logging to an external file and found that the hang or crash always occurs during the delay.
I removed the Delay from the loop and the problem disappeared. (I'm sure glad I have a multi-CPU system though, as it ramped one CPU up to 100%.)
I conclude that this is not an image processing related problem, but actually a problem with Delay or semaphores or scheduling in Pharo.
I'm continuing my efforts to narrow the problem down.
TF
On Mon, Dec 13, 2010 at 2:19 PM, Tony Fleig <tony.fleig@gmail.com> wrote:
I tried using the following background changer for Pharo (from http://book.pharo-project.org/book/CustomizingPharo/PuttingABackgroundPictur...). All was well and it nicely changed the background image to various images from socwall.com. I walked away and when I came back, Pharo was no longer running.
To make a long story short, on Linux and OS X (I did not try Windows), after some period of time, regardless of whether I am actively using Pharo, Pharo either hangs (becomes unresponsive to input, using 100% CPU, images no longer changing) or disappears abruptly. I tried several variations of the script, including loading images from a local directory (i.e. no network code at all) and even loading images into an ImagePreview morph.
In all cases, Pharo eventually either aborts or hangs. I have found nothing in the logs to indicate what happened -- no entries at the time of the abort or hang at all. Decreasing the delay seems to make it happen sooner; I can usually make it happen within 15 minutes of execution with a 2 second delay. It seems to happen more quickly when changing the background image than in an ImagePreview morph.
I monitored Pharo's memory usage and it increased from 106 MB to 109 MB during the execution. Plenty of free memory on the system.
My questions are:
1. How to debug this? Log to a file to see where it is hanging?
2. How to regain control of a hung Pharo. I tried Cmd-<everything> to no avail.
3. Does anyone have any idea what might be happening? Some resource being used up, a race condition, etc.?
Here's the original script
[[[ | rx str url form | str := (HTTPSocket httpGet: 'http://www.socwall.com/browse/index.php?wpLimit=1&wpSortby=8') contents. rx := '.*(http\://.+tb_.+\.jpg).*' asRegex. url := (rx matches: str) ifTrue: str := (rx subexpression: 2) copyWithRegex: 'tb_' matchesReplacedWith: '' ] ifFalse: [ nil ]. url ifNotNil: [ form := ImageReadWriter formFromStream: (HTTPSocket httpGet: url). World backgroundImage: form layout: #scaled]] on: Error do: [:ex| ]. 1 minute asDelay wait ] repeat ] newProcess name: 'Random background changer'; priority: Processor userBackgroundPriority; resume
Regards, TF