BTW, I don't know why the stats reporter multiplies by a factor, maybe
to stay backwards compatible with some perception that people expected?
Simulation FPS is supposed to be constant. In the case of OpenSim, the
user experience doesn't change if we increase this rate beyond 11/sec.
If it goes below that, however, then that's a sign that the simulation
is stressed.
I refer anyone interested in this to documentation about simulations in
general. Here's a good tutorial that I point students to in one of my
courses:
http://buildnewgames.com/real-time-multiplayer/
Scroll down to the part about "game loops"
On 3/2/2015 11:16 AM, Sean M wrote:
There are 3 frame rates: /simulation/, /physics/, and /client/.
Please, someone correct me if I am wrong: the /simulation fps/ is how
many simulation loops can be processed in a second, where each loop
processes physics, scripting, region updates, etc; /physics/ /fps/ is
just how many physics loops get processed per second, where each loop
calculates collisions, gravity changes, and other movement updates for
all appropriate objects in a region Both physics and simulation
(phys/sim) fps are server-side. The fps the /client/ is concerned with
is graphics rendering on the viewer (firestorm, singularity, etc) and
is literally how many visual frames/shots are displayed per second to
the client. From a client point of view, 11fps is low because that is
a low amount of image updates the client is visually seeing on their
viewer. I am concerned with the simulation and physics FPSs being
reported with highly inflated numbers. I want to use sim and phy FPSs
as measures of how my region is performing but concerned that the
correctionFactor of 5 is invalidly skewing these metrics, making both
fps useless.
Michael, or anyone else, do you know why OpeSim ticks at 11 fps? Why
11? Is my understanding of what constitutes a "frame" correct?
On Mon, Mar 2, 2015 at 1:37 PM, R.Gunther <ri...@rigutech.nl
<mailto:ri...@rigutech.nl>> wrote:
11fps ? is that not very low. 22fps gives more rome or 33fps.
But i admit that i read fps maby wrong, and have nothing today
with the framerate or smoothness on the screen..
On 2015-03-02 19:28, Michael Emory Cerquoni wrote:
The reason physics and scripting are locked at 11fps is because
this is what the OpenSimulator heartbeat ticks at, the reason it
is multiplied is to satisfy the viewer statistics, I am not sure
its possible to have it report the legitimate numbers without
some wierd side effects, but I could be wrong, you would have to
experiment, I suspect though that changing this could lead to a
lot of badness.
On Mon, Mar 2, 2015 at 1:23 PM, Sean M <mondesire.s...@gmail.com
<mailto:mondesire.s...@gmail.com>> 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.
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