Forged Alliance Forever

Re: Desyncs in local replays

2013-07-15T21:36:42+02:00

if someone is interested to check this:
the live replay desynched at about 21 minutes

koecher's game.log: http://pastebin.com/GiUEzprf
koecher's forever.log: http://pastebin.com/ki0uyRSp
my replay.log: http://pastebin.com/SsFwr88M
replay attached

first warnings about desync (in replay.log)

warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (RA_Syava).
warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (DoshNEGGER).
warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (GFY_DePonny).
warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (Voodoo).
warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (Lainelas).
warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (Koecher).
warning: Checksum for beat 12550 mismatched: c0f97dace51b4cfa69891afa057adf99 (sim) != de2c1b45ae81b18ff57a5248265c3ebe (Deja-Vu).

Statistics: Posted by Myxir — 15 Jul 2013, 21:36

Re: Desyncs in local replays

2013-07-13T10:42:06+02:00

RoundTabler wrote:
What about when desyncs happen in game? That is worse.

It's rare. (maybe had 2 in 6 years -not counting testing mods-).

Statistics: Posted by Ze_PilOt — 13 Jul 2013, 10:42

Re: Desyncs in local replays

2013-07-13T10:41:33+02:00

Well, this is not the topic.

Statistics: Posted by Ze_PilOt — 13 Jul 2013, 10:41

Re: Desyncs in local replays

2013-07-13T00:35:27+02:00

rootbeer23 wrote:
1) you need to read the document to even start commenting on the issue.
2) it is very much relevant to replay desyncs
3) replay desyncs happen on player disconnect
4) there are no in-game desyncs in supcom FA (super-rare exceptions are irrelevant)

All the desyncs that I've ever seen outside of casts have been ingame.

Statistics: Posted by RoundTabler — 13 Jul 2013, 00:35

Re: Desyncs in local replays

2013-07-13T00:04:02+02:00

1) you need to read the document to even start commenting on the issue.
2) it is very much relevant to replay desyncs
3) replay desyncs happen on player disconnect
4) there are no in-game desyncs in supcom FA (super-rare exceptions are irrelevant)

Statistics: Posted by rootbeer23 — 13 Jul 2013, 00:04

Re: Desyncs in local replays

2013-07-12T23:48:01+02:00

Ze_PilOt wrote:
That's not the problem we are talking about here.

In happens in replays, not in game. Forget all the article is saying, it doesn't apply.

What about when desyncs happen in game? That is worse.

Statistics: Posted by RoundTabler — 12 Jul 2013, 23:48

Re: Desyncs in local replays

2013-07-12T23:45:02+02:00

That's not the problem we are talking about here.

In happens in replays, not in game. Forget all the article is saying, it doesn't apply.

Statistics: Posted by Ze_PilOt — 12 Jul 2013, 23:45

Re: Desyncs in local replays

2013-07-12T23:00:09+02:00

Ze_PilOt wrote:
It doesn't happen in game. It's in replay. You need more information before being helpful.

According to an article (and everything else I've read about desyncs) someone linked to in one of the desync threads by a supcom engine expert (http://www.altdevblogaday.com/2011/07/09/synchronous-rts-engines-and-a-tale-of-desyncs/), a desync happens when an action by one of the players results in the a different result in each of their simulations (example, player A makes attack command, player A's simulation says a unit X dies, player B's simulation says unit X is still alive --> desync happens).

And it's obviously possible to know exactly on what command the game start desync. A pattern can emerge.

I know. Its just time consuming.

Statistics: Posted by RoundTabler — 12 Jul 2013, 23:00

Re: Desyncs in local replays

2013-07-12T22:25:42+02:00

It doesn't happen in game. It's in replay. You need more information before being helpful.

And it's obviously possible to know exactly on what command the game start desync. A pattern can emerge.

(and no, it's not when someone disconnect without using the score menu).

Statistics: Posted by Ze_PilOt — 12 Jul 2013, 22:25

Re: Desyncs in local replays

2013-07-12T22:06:05+02:00

Ze_PilOt wrote:
It does not happen during a game, so no. Only for replays.

Also, comparing replay is useless too. They all desync or none desync. If they don't then post them.

Doesn't the desync happen when two players games diverge? If this is true, then it would happen in game. It would be super nice if we could detect what the divergence was. This seems practically impossible though. :/

Statistics: Posted by RoundTabler — 12 Jul 2013, 22:06

Re: Desyncs in local replays

2013-07-12T17:05:32+02:00

It does not happen during a game, so no. Only for replays.

Also, comparing replay is useless too. They all desync or none desync. If they don't then post them.

Statistics: Posted by Ze_PilOt — 12 Jul 2013, 17:05

~q1021

2013-07-12T17:04:11+02:00

Ze_PilOt wrote:
You could imagine a program that send to FA each packet very slowly (like a very laggy connection) while printing it into a file, so it's easy to catch what command cause the desync.

Basically the livereplay server with an induced lag.

Would it be possible to do this in a 'debug the game' match? Or, would it help to compare the replays from the different players to see how they differed (unless they wouldn't, because it just records inputs?)?

Statistics: Posted by RoundTabler — 12 Jul 2013, 17:04

~q1021

2013-07-12T17:04:35+02:00

EDIT: Double post

Statistics: Posted by RoundTabler — 12 Jul 2013, 17:02

Re: Desyncs in local replays

2013-07-11T18:39:36+02:00

You could imagine a program that send to FA each packet very slowly (like a very laggy connection) while printing it into a file, so it's easy to catch what command cause the desync.

Basically the livereplay server with an induced lag.

Statistics: Posted by Ze_PilOt — 11 Jul 2013, 18:39

Re: Desyncs in local replays

2013-07-11T18:36:29+02:00

you have to simulate a replay at least up to the point where the desync happens to distinguish it
from a synced replay.
either that or you come up with a set of equations that is simpler and that can describe every state
variable of the simulation when used on the replay.

here is the long answer: http://www.altdevblogaday.com/2011/07/0 ... f-desyncs/

Statistics: Posted by rootbeer23 — 11 Jul 2013, 18:36