[Opensim-dev] [Non-DoD Source] Re: Still on Sim and Phys Frames per Second (FPS) (UNCLASSIFIED)

Mon Nov 9 16:37:17 UTC 2015

Classification: UNCLASSIFIED
Caveats: NONE

+1 dz

I'm not trying to start a flame war, so pls take these comments as my own 
opinion.

To be honest, I don't understand how the counter-argument to accurate 
reporting could possibly be taken seriously.  We have done some intense 
troubleshooting on the OpenSimulator to try to find where instabilities and 
performance enhancements can make most sense.  Pandering to the users by 
artificially inflating the numbers does no one any good and is quite frankly, 
weak sauce.  I'm sorry the lag meters don't work anymore, but that is the 
consequence of improperly reporting the stats in the first place.  The correct 
fix here isn't to re-break stats reporting.

Secondly, I don't understand how the Devs plan(!) to address the three major 
components of the CORE that need work to improve stability and scalability. 
We (MOSES) are testing the new PhysX addition and could not do our jobs 
without proper stats reporting. In fact, months of work (and money) was wasted 
last year when we attempted to address physics issues and profiling only to 
find out we couldn't trust the data we were collecting!

Our next work will involve addressing the client manager issues and will 
hopefully yield a workable architecture to allow dozens of people to log in 
simultaneously without lag or impact on the rest of the simulator.  Again, 
can't do this without proper stats reporting.

Think of this as a MacOSX moment.  Might break some old things, but in the end 
you will be better for it.

v/r -doug

Douglas Maxwell, Ph.D.
Science and Technology Manager
Virtual World Strategic Applications
U.S. Army Research Lab
Simulation & Training Technology Center (STTC)
(c) (407) 242-0209

-----Original Message-----
From: opensim-dev-bounces at opensimulator.org 
[mailto:opensim-dev-bounces at opensimulator.org] On Behalf Of dz
Sent: Saturday, November 07, 2015 8:54 PM
To: opensim-dev at opensimulator.org
Subject: [Non-DoD Source] Re: [Opensim-dev] Still on Sim and Phys Frames per 
Second (FPS)

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The issue is promoting accurate reporting of basic performance measurement 
statistics.  ( something that has  not  achieved  nearly enough serious 
attention )

Significant money and manpower is currently being directed at efforts to 
improve simulator performance.
It is a simple fact that the continued funding of these efforts  relies on 
documenting the ACTUAL improvement  against the  ACTUAL original performance 
characteristics.
It is impossible to justify these efforts  when the reported numbers  are 
"made up"  and  THAT fact is not documented except in some obscure comment 
left behind in the source code.

It is unfortunate that the original decision to include a  "Fudge factor 
multiplier" has created a pool of  mis-informed  users ( including myself and 
the  viewer developers   ) .
This mistake was complicated  by the fact that until very recently there was a 
philosophical divide that prevented  OpenSim and viewer developers from 
cooperating on issues like these.
This decision to "play pretend" with performance stats effectively damaged the 
reporting credibility of everyone  who published  these inaccurate  results, 
It also created  a rift between the OpenSim and viewer developers  over the 
decision to NOT discuss  the impact  of  implementing the change.   The fact 
is,  there are  numerous places in the OpenSim framework  where numbers  are 
"made up"  just so that  a number appears in performance reports.  That an 
effort is being made to correct those  sources of  mis-information should be 
welcomed.

It seems to me that the decisions  made by core  should be made in favor of 
supporting the ongoing efforts  to accurately document and improve simulator 
performance.
Justin realized this and lead many of the efforts  to add some measurement 
metrics.    Even  with those efforts, we still cannot  measure  basic 
statistics like Events per Second sent to the script engine, or tie those 
events to whatever script is handling them.  This makes  identifying the 
scripts  ACTUALLY responsible for "lagging" a region impossible using the 
traditional  TOP SCRIPTS report in region manager window.

I would  agree that a simple solution might be to allow grid managers  to add 
back the Fudge Factor to appease their  vocal users, but  would disagree that 
the PROPER decision  should be to continue to report inaccurate results.  It 
would be  just as easy  to implement a  multiplier in the  viewer code "Lag 
Meter",  This  would also allow the accurate reporting of  statistics in the 
Advanced Statistics window  and  administrative reporting.  I believe it was 
also one of the suggested resolutions put forth by the viewer developers... It 
should be clear to anyone who has spent time in world  that the "lag meter" is 
incorrect...  You can walk, build, chat  and TP with the same  level of sim 
performance as you could  before the  numbers were changed.  We've overlooked 
the fact that viewers have behaved  differently  in OpenSim and  "that other 
grid"  for years.   Why is it  "all of a sudden"  CRITICAL  that this one 
viewer feature  HAS to be the same?   In these days  when  core developers 
are releasing  viewers, I cannot understand the urgency of accommodating a 
minor feature of  one viewer whose developers have already demonstrated a 
willingness to work with OpenSim to tailor a configuration to meet our needs.

On Sat, Nov 7, 2015 at 1:19 PM, Melanie <melanie at t-data.com < 
Caution-mailto:melanie at t-data.com > > wrote:

	The issue here is the so-called "lag meter". Since removal of the
	multiplier, this reports all opensim regions as laggy, without
	exception. Users' trust in the "lag meter" is damaging OpenSim
	reputation. This is not a value that is merely for display; the
	viewer uses this value for computations that are then used to
	"judge" a sim to be "laggy" if it's below 35 or so fps. OpenSim now
	always reports a lesser value. This is damaging and needs to be made
	configurable and by default match the viewer's expectations.

	- Melanie

	On 07/11/2015 16:38, Seth Nygard wrote:
	> While I understand the arguments surrounding the original decision to
	> report values closely matching "the other grid", IMHO doing so created
	> an incorrect understanding in many users' minds of how things work
	> and/or behave.  We are not that other grid and should never pretend to
	> be.  Had figures been reported correctly in the beginning then there
	> would be no confusion now surrounding this subject.  However avoiding
	> confusion is a poor reason to roll back and once again report the
	> artificially inflated values.   It is better to simply educate and make
	> it clear that the value of 11fps is indeed the correct value to expect,
	> and is in fact the true value things always have ran at despite what any
	> inflated reported value said.
	>
	> It is true that many scripts and tools have already been written to use
	> the inflated values but they can all be changed with relative ease.  The
	> viewers already have many aspects that are different for Open Simulator
	> so they can be changed easily as well for new versions also with
	> relative ease.  All we need to do as a community is establish what the
	> correct and expected values are and then document and communicate them.
	>
	> As a user, scripter, tool developer, and grid manager, I for one want to
	> see true and accurate values for any and all metrics regardless of where
	> they are shown or how they may be used.  I therefore am firmly against
	> rolling back to any older artificially inflated values.
	>
	> Regards
	> -Seth
	>
	>
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