High load when trying to fetch image

Question

High load when trying to fetch image

voegtlel opened this issue 5 years ago · comments

Describe the bug
When trying to fetch an image, the fetch_buffer method runs in an infinite loop without threaded sleeps.

Expected behavior
The method fetch_buffer should use proper events to synchronize with the acquisition thread. Or rather use a queue.Queue for fetching ready buffers.

Desktop (please complete the following information):

OS: N/A
Python: 3.6 (doesn't matter)
Harvester: 1.0.3
GenTL Producer: N/A
Camera: N/A

Additional context

Related source code lines:

https://github.com/genicam/harvesters/blob/master/src/harvesters/core.py#L2074 (this is where the cpu-hungry loop starts)

https://github.com/genicam/harvesters/blob/master/src/harvesters/core.py#L1976 (this is where the synchronization must happen)

https://github.com/genicam/harvesters/blob/master/src/harvesters/core.py#L1574 (maybe use queue.Queue here)

Kazunari · Answer 1 · Mon Feb 24 2020 22:14:51 GMT+0800 (China Standard Time)

@voegtlel Hi, thank you for your valuable feedback. Okay, I will review the design and try to improve it. /Kazunari

Kazunari · Answer 2 · Tue Feb 25 2020 20:26:50 GMT+0800 (China Standard Time)

JFYI: Working on it. It seems to be promising. I will let you know once it turns ready. :-)

Kazunari · Answer 3 · Fri Feb 28 2020 22:27:19 GMT+0800 (China Standard Time)

@voegtlel Hi. I have just committed a changeset that resolves this issue to the following branch:

https://github.com/genicam/harvesters/tree/_issue_120

Could you try that out when you can, please? I need your feedback to judge if I should merge this or not. You can manually install Harvester with the following command in the working copy:

$ git clone https://github.com/genicam/harvesters.git && cd harvesters && git checkout origin/_issue_120 && python setup.py install

Note that perhaps you should uninstall Harvester in advance if you have already installed it:

$ pip uninstall harvesters

Thanks,
Kazunari

Kazunari · Answer 4 · Thu Mar 05 2020 00:11:51 GMT+0800 (China Standard Time)

@voegtlel The 2nd prototype has been available.

Kazunari · Answer 5 · Thu Mar 05 2020 09:41:52 GMT+0800 (China Standard Time)

@voegtlel Please note that I would not be able to merge the branch without your confirmation. ;-)

Lukas Voegtle · Answer 6 · Thu Mar 19 2020 02:29:32 GMT+0800 (China Standard Time)

Oh I'm sorry, I was on vacation, and now I'm in quarantine, so I don't have the hardware to verify your changes :(

I checked your commits though, and they basically look fine. I only see one issue: If you specify a very long waiting time for fetch_buffer, you cannot exit that method. I usually solve this by enqueuing None as a special "exit" value. But I guess looping with a small timeout should also work fine.