Multiplayer continues to be unplayable

[Blackspectre]

I know I have made a post or two on this topic, but this issue still remains an enormous and glaring issue with the multiplayer in this game. With the talk Ive read of getting ready to push the stable multiplayer, I feel that it is very necessary to re-iterate that the multiplayer is, in fact, still not stable. I applaud the fixing of countless de-sync and crash bugs, but the download of the map to peers is still prohibitive in terms of playability.
My friend and I have been doing some tests to help identify the issue, as it has been suggested in the past that it is not a factorio issue, but that maybe it is an issue with our ISPs, Modems, Routers, etc etc.
So we went back to 11.1
When we first began playing, we did not have these map download speed issues (seriously, in 11.10, it takes nearly 5 minutes to download a fresh map, and an hour+ to download a map that is 30 mins into gameplay.)
So anyways, 11.10, map download speed is atrocious.
So about 30 mins ago we went back to 11.1, and the fresh map was downloaded nearly instantly, and maps that have several hours on them take 2 minutes at the longest to download.
since 11.1 map download speed works great, and 11.10 does not, I believe this is undeniable evidence that this is a factorio issue. We are currently going through each of the versions to test to see which patch broke the download speed, and will respond with that information. If memory serves me correctly, it was 11.4, but we will make sure.

I implore, beg, and plead with the developers to please address this issue. We love this game to death, and cannot play it because we are ultimately playing without being able to save (which in a game like factorio, that can have 60+ hours of gameplay, is prohibitive).

And to those who will say, "oh, just go play 11.1 then", well, we would, but the de-sync nightmares still exist in those patches, which are prohibitive for a different reason =/

Also, if a developer reads this, the map save size reduction is terrific, but looking at it in terms of math, a 58% size reduction is a 58% speed increase. Utilizing full bandwidth on the transfer however is proving to be on the magnitude of a 10,000% increase. Please just check to see if something was unintentionally broken in the P2P code. Again, we will do our best to precisely discern exactly which patch broke it. (hopefully that will help narrow it down)

[cube]

There are two separate problems in the map upload:

One is, that only one of the players is used as a source of the map. This is probably caused by a minor desync in the map download preparation which causes different players to have different CRC of the map they provide and that means that only one them has to be selected.

The other problem is with the raw speed, and we don't know a reason why this doesn't work correctly yet.

... But both of these problems are on the list and will be fixed soon(ish). Sorry for the problems.

Thanks a lot for trying the versions. Finding the one in which this started would be _very_ helpful :-)

[Blackspectre]

Update for Cube:

Each transfer was tested with a freshly generated map with nothing built.
We tested the load times, and my memory was right.

11.3 had a 6 second map download
11.4 had a 118 second map download

So somewhere in the 11.4 patch is something that slowed the transfer speed by 2,000%!

I hope this helps you isolate the issue. If you have any more questions about the problem, just let me know.

Thank you so much for your attention to this! You guys rock!

[cube]

It's probably fixed: https://forums.factorio.com/forum/vie ... =10#p67651

The fun thing was that the problems were caused by a fundamental flaw in the algorithm that didn't change between 0.11.3 and 0.11.4. The difference you found must have been a caused by different packet loss on your network between the two experiments.

[Quazil]

There is still an issue in 0.12.29.

I have a dedicated VPS running the server on Linux (Ubuntu) and it never downloads faster than 1Mbps and slows down to ~100kbps.
I download saves games to my machine from the server via ssh/scp at 20mbps.

[daniel34]

• Bugfixes
  • Improved map download speed when connecting to multiplayer game. (20532)

As this was only recently changed in 0.12.31 you'll need to opt in to experimental releases or wait until it becomes stable.

Updating to experimental:
For the standalone version enable experimental updates in the options, for the steam version right-click the game in the library --> Properties --> Betas and select experimental from the dropdown.

If you're interested in the technical details: Friday Facts #136 - Map Transfers