Responsiveness regression (even without a drawing)

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e-rock
Registered Member
Posts: 2
Joined: Sat Dec 12, 2020 10:40 pm

Responsiveness regression (even without a drawing)

Post by e-rock » Sat Dec 12, 2020 10:53 pm

I installed and used QCad a couple months ago and it worked very well.

I just re-opened QCad to do a new project, and it is much slower than before. Simply moving the mouse on a new, empty drawing, is laggy and slow to respond and can bring CPU utilization close to 100%. I tried draft mode and tried turning Snap to Free or Grid, same effect. This is clearly different than before, when I could move the mouse cursor in an actual drawing and successfully use snap to grid or various drawing elements smoothly and responsively.

Machine is
- Linux (Ubuntu 20.04)
- QCad 3.25.2.0 (3.25.2)
- Ryzen 7 3700X, 64GB RAM, SSD, Radeon RX 570

I haven't observed any performance issues in any other applications.

Since it worked before, and since it is an issue even when I have a completely empty drawing, I suspect some kind of configuration issue, but I'm not sure what to investigate.

thanks,
eric

CVH
Premier Member
Posts: 3415
Joined: Wed Sep 27, 2017 4:17 pm

Re: Responsiveness regression (even without a drawing)

Post by CVH » Sun Dec 13, 2020 2:33 am

Hi,
Indeed very troublesome...

First: Your post comes from https://www.qcad.ch/rsforum/ where I could not log in to.
Is that the site that is openend by Menu..Help..Forum?

Second: Did you installed other applications meanwhile in those months?
Are you sure it is the same installation? The licenced PRO version?
You didn't mix up the trial, CE and the PRO version?

Maybe related:
https://qcad.org/rsforum/viewtopic.php?f=34&t=7814
Several solution posts by Andrew also refer to the QT 5.14 install.

You could try resetting QCAD:
https://qcad.org/en/tutorial-resetting- ... figuration.

In doubt then remove any QCAD installation and try a clean reinstall QCAD PRO from your download area.

Regards,
CVH

e-rock
Registered Member
Posts: 2
Joined: Sat Dec 12, 2020 10:40 pm

Re: Responsiveness regression (even without a drawing)

Post by e-rock » Sun Dec 13, 2020 3:30 am

Whoops. I came to qcad.ch via Google and didn't even notice because it uses a logo that clearly says "qcad.org" :) Odd, I guess it's a different entry point for the same forum database?

This is the free version. I don't know of anything else notable I've installed, but I tried clearing the config file and it is working better again. Thank you for the tip; if it happens again I'll dig a bit more into the config file to try to figure out what's going on.

Thanks,
Eric

CVH
Premier Member
Posts: 3415
Joined: Wed Sep 27, 2017 4:17 pm

Re: Responsiveness regression (even without a drawing)

Post by CVH » Sun Dec 13, 2020 4:00 am

Hi,
1: You posted on the PRO forum.
Report your topic and ask for moving it to the CE forum.
Report.png
Report.png (3.49 KiB) Viewed 9139 times

2: Trial or CE?
Did you remove the trial mode?
viewtopic.php?f=76&t=4668

3: There is nothing much in the config that you should alter unless Andrew tells you to.

Regards,
CVH

jvalencia
Full Member
Posts: 51
Joined: Mon Jun 29, 2015 8:26 pm

Re: Responsiveness regression (even without a drawing)

Post by jvalencia » Mon Jan 04, 2021 1:21 pm

Hello, I'm facing the same issue.

I'm on Ubuntu 20.04.
Ryzen 5 1600
Nvidia GTX 1650
Qcad 3.25.2 (both qt5.8 and qt5.14)

So I tracked the issue to the number of threads used by QCad under Graphics View -> Appearance. When set to 1, it behaves fast as always. When set to auto (6), it lags. When set to a bigger number of threads, it lags even more.

I hope this helps you track down the problem.

Regards.

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andrew
Site Admin
Posts: 9036
Joined: Fri Mar 30, 2007 6:07 am

Re: Responsiveness regression (even without a drawing)

Post by andrew » Mon Jan 04, 2021 2:06 pm

A higher number of threads doesn't automatically mean it will perform better as there's an overhead of drawing on different targets and bringing those together again. It's a balance between the advantage of multithreading and the disadvantage of this overhead. Also, an empty drawing would always be slower using multiple threads. Multithreading only really makes sense if you frequently work with rather complex drawings. Simply use whatever number works best for you (typically 1-4).

jvalencia
Full Member
Posts: 51
Joined: Mon Jun 29, 2015 8:26 pm

Re: Responsiveness regression (even without a drawing)

Post by jvalencia » Mon Jan 04, 2021 5:20 pm

Makes sense. I have to say that I didn't touch that setting, it came by default set to 6.
I suspect this is the same problem OP is having.

Maybe set it by default to 1 and increase it if your workload needs it?

jvalencia
Full Member
Posts: 51
Joined: Mon Jun 29, 2015 8:26 pm

Re: Responsiveness regression (even without a drawing)

Post by jvalencia » Mon Jan 04, 2021 6:11 pm

Opps apparently I'm posting on the community edition. Mine is Pro edition.

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