ThorstenB > On 11.05.2012 10:21, Renk Thorsten wrote: > > The problem with that consequence is: As you switched all loops off, > > the Nasal part of Advanced Weather ceased to run completely and all > > that's left is the same cloud-generating functionality which is > > responsible for Basic Weather (C++ and shader work). If killing all > > Nasal did not solve the problems, then they can't be caused by Nasal, > > and porting to C++ will not fix them. > > Not quite true. A significant part of Nasal-related frame rate impact is caused > by garbage collection. Its delay/jitter only depends on the number of Nasal > objects and their references which need to be searched. > Increasing the number of Nasal objects (code+data) existing in memory also > increases the delay. > > The amount of Nasal code which is actually being executed only influences > the g/c frequency, i.e. whether the effect is visible every few seconds vs > several times per second. > > This is why we are loading large Nasal modules, like advanced weather, on > demand only (= only when feature enabled). We're not unloading objects > when disabling a feature though - this usually requires restarting fgfs. This > should be remembered when comparing such features (i.e. restart fgfs after > disabling advanced weather etc). >
Thanks for that explanation. In the light of this I did some more testing. Switching from Basic to Advanced Weather increases the time spent in the events submodule from a stable 44 ms to over 1000 ms unstable. Setting all flags to 0 reduces this to 90 ms. Switching back to Basic, the time drops to 75. Adding more nasal loops into the equation by lowering the flaps and gear on the Seahawk, I think I can see the effect as a slight increase in the time spent in the events submodule. I'm not clear how deleterious having one submodule taking significantly more time than any other might be. If that is a problem, then large nasal script are not a good idea even if we only enable them on demand. The instability is clearly not a good thing, but is this a GC problem? If it is, then again, large nasal scripts are not good. Perhaps James can fix the GC issue, and this issue will disappear. I hope so. Vivian ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
