Thanks Justin, Dahlia, Michael, and everyone. I now have a better understanding of the way FPS is calculated and of the correction factor.
-Sean M. On Monday, March 2, 2015, Justin Clark-Casey <[email protected]> wrote: > I think this has already been said but just to summarize. > > * The 11 fps are the number of scene frames processed - opportunities > where avatars may be notified about changes in the scene. > > * Each of these scene frames is associated with a physics process where 5 > physics frames are processed in each frame. Hence 11 * 5 = 55 fps. > > * Why this number? Others may know better but my guess is that it's > related to the frequency of updates expected by the viewer. Teravus may > well know more if he's still around. > > * Changing m_reportedFpsCorrectionFactor will do nothing except change the > server FPS stat. > > * Changing MinFrameTime will change the number of scene frames. From my > work in the past, you would also need to adjust other parameters like > physics frames to stop things going haywire (this was with ODE, Bullet > might work differently). I expect you also wouldn't gain much if anything > in scene fidelity. > > On 02/03/15 18:23, Sean M wrote: > >> Greetings, >> >> We at the MOSES project have noticed Simulation and Physics frames per >> second (FPS) have a few issues that we are trying >> to resolve. The issues are producing suspicious performance statistics >> for the analysis of the current version of >> OpenSim that we are running. >> >> First, there is a correction factor (m_reportedFpsCorrectionFactor) that >> the raw SimFPS is multiplied by. The comment in >> the following line is a bit curious because it indicates that the FPS is >> artificially inflated to "lie" about the actual >> FPS being so low: >> >> OpenSim/Region/Framework/__Scenes/SimStatsReporter.cs: Line 317 >> // We're going to lie about the FPS because we've been lying since 2008. >> The actual FPS is currently >> // locked at a maximum of 11. Maybe at some point this can change so >> that we're not lying. >> int reportedFPS = (int)(m_fps * m_reportedFpsCorrectionFactor); >> >> Also, lines 174 and 227 mention the use of this correction factor. >> >> Second, this multiplier also comes into play in the Scene where there is >> a MinFrameTime, which seems to be the minimum >> reported amount of time to process a frame: >> OpenSim/Region/Framework/__Scenes/Scene.cs:Line 723 >> >> Both of these variables, the correction factor and MinFrameTime, are >> concerning from a statistics view point as they are >> generating skewed and massaged numbers; therefore, I have a few questions: >> >> 1) Is it commonly known that Sim and Phy FPSs are inflated to maintain >> the "lie"? And if so, will it be corrected to be >> an accurate reporting of processed frames per second? >> >> 2) What exactly are the definitions for OpenSim's Simulation (Sim) FPS, >> Physics (Phy) FPS and a frame (I have found >> conflicting and vague definitions on the wiki)? >> >> 3) What are the known performance consequences of setting the >> m_reportedFpsCorrectionFactor to 1 and MinFrameTime to 0? >> >> Thanks, >> Sean M. >> >> >> _______________________________________________ >> Opensim-dev mailing list >> [email protected] >> http://opensimulator.org/cgi-bin/mailman/listinfo/opensim-dev >> >> > > -- > Justin Clark-Casey (justincc) > OSVW Consulting > http://justincc.org > http://twitter.com/justincc > _______________________________________________ > Opensim-dev mailing list > [email protected] > http://opensimulator.org/cgi-bin/mailman/listinfo/opensim-dev >
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