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FlightGear Newsletter September 2014: Difference between revisions
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FlightGear Newsletter September 2014 (view source)
Revision as of 22:15, 18 September 2014
, 18 September 2014→Performance Issues
(Added an "In The Hangar" Section and the A300-600) |
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As some of you may know from working with Nasal code: listeners are not in and of themselves expensive, but running identical listeners over and over again each frame is getting unnecessarily expensive quickly. This doesn't just apply to scripting space, but also to C++ space - here, it's the sheer performance offered by native C++ code that makes it much harder to identify such problems, because code that would bring the simulator down to its knees in Nasal may very well still be "fast enough" for most people with fast computers, despite being still very much "broken", and plain wrong. | As some of you may know from working with Nasal code: listeners are not in and of themselves expensive, but running identical listeners over and over again each frame is getting unnecessarily expensive quickly. This doesn't just apply to scripting space, but also to C++ space - here, it's the sheer performance offered by native C++ code that makes it much harder to identify such problems, because code that would bring the simulator down to its knees in Nasal may very well still be "fast enough" for most people with fast computers, despite being still very much "broken", and plain wrong. | ||
As can be seen on the devel list, Torsten has been spending the last weeks troubleshooting the effects system, which isn't exactly straightforward because its original developer is not currently involved in FlightGear, and the code is pretty sophisticated and even multi-threaded (which means that parts of the code may be running concurrently on different CPUs) - however, Torsten did report pretty significant performance improvements recently - he's just pushed his work to a new branch so that other developers (and people building from source!) can have a look and test his changes and report feedback/issues - this will probably mean that it may take a few weeks until all the feedback has come in and implemented - but performance should be improved significantly by then - which also addresses the whole "when will 3.2 be released" question. | As can be seen on the devel list, Torsten has been spending the last weeks troubleshooting the effects system, which isn't exactly straightforward because its original developer is not currently involved in FlightGear, and the code is pretty sophisticated and even multi-threaded (which means that parts of the code may be running concurrently on different CPUs) - however, Torsten did report pretty significant performance improvements recently - he's just pushed his work to a new branch so that other developers (and people building from source!) can have a look and test his changes and report feedback/issues - this will probably mean that it may take a few weeks until all the feedback has come in and implemented - but performance should be improved significantly by then - which also addresses the whole "when will 3.2 be released" question. Meanwhile, Stuart has joined Torsten to help with fixing the bug: | ||
{{FGCquote | |||
|Acutally, Stuart is working on this and has improved the UniformCache I started with. He has a much better insight in the Effect system than I do. | |||
His work is much better than mine but still has some breakage for existing shaders, most prominent one is ALS. | |||
We are still investigating whats going on there and I have to ask for just some more patience.<br/> | |||
Torsten | |||
|{{cite web |url=http://sourceforge.net/p/flightgear/mailman/message/32846172/ | |||
|title=<nowiki>Re: [Flightgear-devel] crash in SGPropertyNode::fireValueChanged</nowiki> | |||
|author=<nowiki>Torsten Dreyer</nowiki> | |||
|date=<nowiki>2014-09-18</nowiki> | |||
}} | |||
}} | |||
Also, Hooray recently built fg on a dual-core netbook with Intel GMA graphics (1gb RAM) to see if/how well Canvas is supported there (some people reported white RTTs due to lack of FBO support) - it is true that doing this more regularly would probably help identify certain issues much earlier - it seems that a few contributors are still trying to spin up FG once in a while on their old computers - Thorsten repeatedly mentioned doing that for regression testing purposes when testing his own work. | Also, Hooray recently built fg on a dual-core netbook with Intel GMA graphics (1gb RAM) to see if/how well Canvas is supported there (some people reported white RTTs due to lack of FBO support) - it is true that doing this more regularly would probably help identify certain issues much earlier - it seems that a few contributors are still trying to spin up FG once in a while on their old computers - Thorsten repeatedly mentioned doing that for regression testing purposes when testing his own work. | ||