Unfortunately not, I suspect that would require some changes to libomv to install hooks to alter behaviour.
It would be easier to drop random packets on the server side but of course then you're not fully simulating the behaviour. On 18/11/14 22:17, Mic Bowman wrote:
justin, does pcampbot allow us to drop random incoming messages? one thing about ec2 instances is that they are (generally) well connected. adding random or bursty packet drops might help test more effectively problems with networking. --mic On Tue, Nov 18, 2014 at 1:51 PM, Justin Clark-Casey <[email protected] <mailto:[email protected]>> wrote: These are all fixable issues, either with pCampbot improvements or distributing pCampbot instances amongst more machines. I expect pCampbot will be built upon to address these points as required. And this year I successfully used 4 Amazon c2 large instances for bot running so a more realistic network load means spinning up more cloud instances. I agree that unless you can reproduce an issue you are shooting in the dark with any changes. And organizing enough real people to reproduce issues on a regular basis and without a huge amount of confusing other behaviour is impossible in practice. On 14/11/14 16:46, Maxwell, Douglas CIV USARMY ARL (US) wrote: Classification: UNCLASSIFIED Caveats: NONE Dr. Lopez, thank you for sharing your paper. Can you tell me where it was peer reviewed and published? I would like to reference it in my dissertation. On the topic of bots, the MOSES team has not been able to compose a NPC agent or bot that accurately replicate the footprint of a human agent on the simulator. We believe this is for many reasons: 1) Bots are usually composed on a server on the same network, not dispersed across the internet. The bots should be software throttled and noise introduced into their connections to approximate random access. 2) Bots aren't using full clients, so they are not filling caches and making the same scene requests as humans in graphical clients. 3) Bots are usually homogenous. They need to be randomly dressed, have random attachments, and have random inventories. 4) Bots need to move randomly and collide with objects in the scene and with each other. 5) Bots need to randomly chat with each other and broadcast locally. We think we can create a NPC solution that satisfies these issues. Will take some thought and development. Has anyone come close to this? Goal: Compose bots/NPCs that can approximate the loads of humans within 90% certainty. Meaning if we load 100 of these artificial agents into the MOSES, we are certain that it will accurately behave as if at least 90 humans are logged in. IMHO, if you can't assign a reliability to a test, then you are just wasting your time. This is basic V&V tenants. v/r -douglas Douglas Maxwell, MSME Science and Technology Manager Virtual World Strategic Applications U.S. Army Research Lab Simulation & Training Technology Center (STTC) (c) (407) 242-0209 <tel:%28407%29%20242-0209> -----Original Message----- From: opensim-dev-bounces@__opensimulator.org <mailto:[email protected]> [mailto:opensim-dev-bounces@__opensimulator.org <mailto:[email protected]>] On Behalf Of Diva Canto Sent: Friday, November 14, 2014 11:05 AM To: [email protected] <mailto:[email protected]> Subject: Re: [Opensim-dev] Modifying the networking stack On 11/14/2014 6:23 AM, Michael Heilmann wrote: Thanks for the responses. I'll go into a little more detail: We have been running several profilers against OpenSimulator on the MOSES grid, and on my development machine. The tests were to examine the loading on the server under several different loads, specifically mesh and physics loads. What we found appears to be that no matter what kind of load we placed on the region, even to the point of becoming unresponsive due to physics and mesh, that scripting and physics load were nowhere near the amount of time spent in OpenSim.Region.ClientStack.__LindenUDP once we had more than one or two avatars logged in. We know from previous investigations at our firewall that network traffic for OpenSim is not that heavy, especially with low numbers of users. If this is a problem, and you are running a recent-ish version of core OpenSim, it sounds like some misconfiguration somewhere. Back in the summer of 2013 we had a problem with the server running OSCC'13; the kernel was configured to run in some sort of special mode that was making everything run badly and unpredictably. We fixed the kernel configuration, and suddenly things started running much more smoothly-- I don't remember the details, but Nebadon may clarify things. OpenSim these days can handle 50 people on a single simulator without much trouble. If you look at figure 7 of my paper (http://www.ics.uci.edu/~__lopes/documents/summersim14/__gabrielova_lopes_prepri <http://www.ics.uci.edu/~lopes/documents/summersim14/gabrielova_lopes_prepri> nt.pdf) you will see the quantification of "without much trouble." I suggest that you reproduce my experimental conditions with pCamBot and check whether your numbers are very different from ours. If they are very different, then there's definitely something odd in your setup, as we were able to reproduce these numbers in several machines. Feel free to contact me directly for details about pCamBot configuration. Bots aren't real viewers, but they are much better for measuring things systematically and detecting problems and bottlenecks than relying on real users driven by real people. The performance you get with pCamBot will be correlated with the performance you get with real users. I ran several Wireshark captures against a Firestorm viewer logging into the MOSES public grid ABWIS region, where we hold our office hours. I saw that with our current configuration, all traffic between the server and my client, with the exception of http CAPS and fsapi calls, were UDP traffic. This is not immediately concerning, as we have simian serve our mesh and textures directly. The messages are mostly binary information, so I could not examine closely, but I did see a lot of messages containing identical ASCII strings, such as the name of my avatar. Hard to say what you saw, but I bet those are the AgentUpdate messages that I mentioned before. The viewer sends at least 10/sec. At points, the viewer sends much more than 10/sec, up to 60/sec. Again, take a look at my paper for understanding what those are, and how OpenSim deals with them since OSCC'13. As I said before, it would be nice to understand why the viewer is so eager to blabber its status to the server when nothing is going on. My primary concern is the amount of time spent handling networking, not necessarily the networking its-self. But there is at least a portion of messages on the UDP pipeline that are either reliable, or perhaps should be; and re-implementing a reliable transport over udp introduces load at the application layer, instead of letting a low-level reliable transport such as tcp handle it. I went to university with a guy who implemented a java networking library completely over UDP, believing that it was faster than a normal TCP socket; but he was neglecting that the networking hardware handles the ACK and retransmission transparently, and without needing for the messages to be handled manually by the application. This may just be my opinion, but since I was going to be ecamining the network stack anyways, and typically in a client-server scenario the ability to maintain a persistent reliable connection where the server can push important events to the client, that it would be a good idea. The points about network throttling and QoS are taken, but wouldn't they also typically affect the UDP stream? Working on MOSES I have plenty of problems dealing with external users who operate on restricted networks, and they cannot see traffic aside from 80 and 443 without dealing with their own IT personnel. The fact that it is HTTP over TCP instead of raw TCP makes no difference once it is on a non-standard HTTP port. I agree that it would be more prudent to look at improving the websocket code and the http server, rather than replace it with a raw TCP socket, especially given that there are multiple plugins, such as jsonsimstats, that use the http functionality directly. I hope that explains my position a little better. I would love to hear if there are other plans/ideas in the community to address time-sinks like this one, networking simply appears to us as a good starting point to increase performance and scalability of the system. _________________________________________________ Opensim-dev mailing list [email protected] <mailto:[email protected]> http://opensimulator.org/cgi-__bin/mailman/listinfo/opensim-__dev <http://opensimulator.org/cgi-bin/mailman/listinfo/opensim-dev> Classification: UNCLASSIFIED Caveats: NONE _________________________________________________ Opensim-dev mailing list [email protected] <mailto:[email protected]> http://opensimulator.org/cgi-__bin/mailman/listinfo/opensim-__dev <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] <mailto:[email protected]> http://opensimulator.org/cgi-__bin/mailman/listinfo/opensim-__dev <http://opensimulator.org/cgi-bin/mailman/listinfo/opensim-dev> _______________________________________________ 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
