2017-02-21 13:27 GMT+01:00 Elvis Stansvik <elvst...@gmail.com>: > 2017-02-15 18:28 GMT+01:00 Gibbs, Matt <mgi...@slac.stanford.edu>: >> Hi All, >> >> I’m working on a Qt-based project to display rapidly updating information >> from a control system. I want to display hundreds of signals, each updating >> at about 10 Hz. As a performance test, I’ve thrown 500 Labels in a grid >> layout, and fire a timer every 100 ms which calls setText on each label. >> This ends up being surprisingly CPU-intensive: on reasonably modern hardware >> (2012 MacBook Pro), I use 70% of one CPU. This doesn’t leave me much >> overhead to do anything else. >> >> Are there any best practices to reduce CPU usage in this case? > > Hm, I don't really have a good answer when it comes to optimizing it > the way you've stated it, but lets get a little philosophical instead: > What human operator of your GUI is going to be able to process all > this visual information? I would have a hard time monitoring even 5 > labels of text updating at that rate. > > My recommendation would be: > > 1. Consider if your really have to show all these sensors, or if the > information they're conveying can be aggregated in some way. > 2. If you really need to visualize them all at once, consider a > simpler presentation than the numerical, such as a bar (should be > cheaper to redraw than a changing text). > > Regarding 1, if the sensors can be grouped in some logical way, you > can present a collection of sensor groups instead. Regarding 2, if the > user wants to look closer at a single sensor, or maybe a (reasonably > sized) group of sensors, you could build some UI for that. > > It would help to know a little more about the user story, is this for > monitoring a system for failures? If so, I think the rule of thumb is > that if nothing is out of the ordinary, the system should not look > visually "busy" (no big movements or bright colors, just subtle > gray/static text). That allows you to use visual movement and bright > colors for error conditions / anomalies. But yea, it would help to > know more about what the GUI is for :)
Another powerful UI design principle is (as I hinted at) "drill down" UIs -- find some way of aggregating the information, and let the user drill down deeper if he/she wants to know/see more. The fidelity you're aiming for (500 numbers, presented numerically @ 10 Hz) is too much bandwidth, not only for your MacBook, for also for any human. Elvis > > Hope that helps a little, even if it wasn't what you asked for. > > Elvis > >> >> Cheers, >> —Matt >> >> Matt Gibbs >> SLAC Accelerator Operations Group >> mgi...@slac.stanford.edu >> _______________________________________________ >> Interest mailing list >> Interest@qt-project.org >> http://lists.qt-project.org/mailman/listinfo/interest _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
