On Tuesday 07 November 2006 20:11, Curtis Olson wrote: > On 11/7/06, leee <[EMAIL PROTECTED]> wrote: > > I suspect that the graphics will prove to be the trickiest problem - it's > > by > > far the greatest resource user - > > Right, in all this we need to remember that in all our past benchmarking, > the graphics themselves account for 90-95% of the workload. OSG provides > some opportunities to thread the graphics rendering itself, but beyond > that, the remaining 5-10% of computational effort is pretty small in > comparison. Further dividing that up into additional threads may not be > such a huge win, unless as Durk says there are tasks that are "bursty" like > metar fetching which has to block on network IO ... that makes a lot of > sense to put into a separate thread, but does anyone realize the pain we > wen through to debug that simple task? And then does anyone recall that a > subsequent patch broke it all again and we had to wind all the way through > the process and figure it all out again. Lot's of pain was endured by at > least a couple developers to make that work. > > So yes, threading does indeed make sense in certain specific contexts, but > we need to be really careful about what we do, exactly why we do, and what > specific peformance benefits we *know* we will get by threading some new > task. > > Curt.
One thing to remember when saying that the graphics accounts for 90-95% of the utilisation is that it doesn't necessarily follow that all the other subsystems get the resources that they require. For example, I'd like to be able to run the autopilot pid controllers at much higher and more consistent rates than is possible now and even though the FDM rates are supposed to be guaranteed, in practice, it doesn't always seem to be the case. Personally, I'm not a fan of 'threading' as a parallel-processing solution, not only because of the problems you mention, but also because it doesn't scale. LeeE ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
