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Attempt to reproduce lag (100k desync)
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This ticket is dedicated to attempt to reproduce lag that is happening on live servers. The repro doesn't actually reproduces the cause of the lag on actual server but simulated a situation where same kind of lag occurs like it does on real server which hopefully might give a better idea what causes the lag. {F24749}


Legacy ID
Steps To Reproduce
  1. Run attached mission desync_repro.Stratis with 3 players on non-dedicated server (host and 2 players)
  2. Start the mission
  3. Player 2 should go back to the lobby and wait there
  4. Player 3 should select "Start test" action in action menu
  5. Player 3 should wait until number in top left reaches 500 and give signal to Player 2 to join the game.
  6. When Player 2 will join, visible number of server should be different from number that Player 2 has, results vary between different tests.
  7. Observe Player 3 freezed for both Host and Player 2.
  8. Sometimes Host will appear freezed for Player 2, sometimes doesn't
  9. After number reached 500 for all players, Player 2 (that was JIP) will have high desync number, up to 100000, apparently the higher difference between what numbers Player 2 and Host see, the bigger desync number is. Sometimes Player 3 will have desync numbers too.
Additional Information

What is going on with the mission:
When player selects "Start test" they send 500 public variable arrays with random values (array of 3 numbers) with each next array having 1 more value than previous one. (init_ns.sqf)

This test does not reproduces the situation happening on live servers, it forces one of clients to send extreme amounts of public variables over network which creates lag very similar to that happening on live server, actual mission (King of the Hill) doesn't send this amount of public variable data.

Additionally repro seem to work ONLY the first time you run the mission after starting the server. With all next mission starts server recieves (client sends?) public variables MUCH quicker resulting in less lag and desync numbers on JIP player. If test fails or you need to run it again MAKE SURE to go back to servers list and create server again.

This repro wasn't tested on dedicated server but I assume result should be similar.

Event Timeline

SaMatra edited Steps To Reproduce. (Show Details)Sep 6 2014, 8:45 PM
SaMatra edited Additional Information. (Show Details)
SaMatra set Category to Multiplayer.
SaMatra set Reproducibility to Sometimes.
SaMatra set Severity to None.
SaMatra set Resolution to Open.
SaMatra set Legacy ID to 2449574513.May 7 2016, 7:23 PM
Bohemia added a subscriber: Dwarden.Sep 6 2014, 8:45 PM