I believe 11 sim FPS is the target value. It would probably never go
above this, but a number consistently lower than 11 fps would
indicate performance problems. If the "lie" is simply a linear
scaling, then it would have no impact in the ability to use the
number as a comparitive statistic. since all such numbers would be
similarly scaled.
I also believe some of these numbers eventually make it to the
viewers and are used to adjust moving entity velocity when the sim is
running slowly. I'm not sure of the exact path but I think "time
dilation" is involved. Altering these values may induced undesirable
movement effects when the simulator is running slower than normal.
Raising the target above 11 would also likely induce issues as other
parts of the code assume 11 is the target.
On Mon, Mar 2, 2015 at 11:16 AM, Sean M <[email protected]
<mailto:[email protected]>> 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 <[email protected]
<mailto:[email protected]>> 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
<[email protected] <mailto:[email protected]>>
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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