Winsock Lag (TCP)

[LunaRebirth]

Hello!

First, I need to clarify that this lag problem is not because of Irrlicht. Winsock is lagging up my program.

I've created an online multiplayer program using Winsock with Irrlicht. Made a server and client for this. When running the server and client on the same PC, everything is perfect and running very smoothly!
But if I have a friend host the server, my client lags TONS. Less than half the normal FPS.

So my questions is.. Would anyone happen to know how to reduce/get rid of this problem?
The lag being client-sided shouldn't happen. I understand server-side lag where other players don't update, but client lag is still happening.

-I'm using ioctlsockets to stop from blocking on Recv.
-I'm checking Recv with sizes using: if ((size = recv(...) > 0)) { ... }
-Unless a client moves, (Presses up,down,left, or right) they do not send data to the server.
-Server does not send your own data to yourself

(It's a multi-threaded server, and the client runs on one thread upon startup -- for sending/recving)

I've followed many steps from multiple tutorials and winsock sites, but no matter what; The clientside lag is still a huge problem!

Any help would be greatly appreciated, If any code snippets would be useful.. Please let me know. Wasn't sure what needed to be shown here.
Thanks!!!

P.S. I don't want to download anything extra like RakNet or Enet, Winsock is free.

[hendu]

Well, what exactly is slow? Add timing calls to your main loop, use binary search to halve the area each time. Can't really give any advice without that info.

[LunaRebirth]

I don't understand what you mean

By slow I mean, If I was to turn my screen in a full 360d angle while I was the one hosting the server, it may take 3 seconds.
If I have a friend host the server, it will take 10+ seconds to fully rotate.
And if I remove the server calls, making it an offline game, it's normal (Like hosting the server and playing client on the same computer). It'd definitely Winosck making the clientside lag

[Ruxify]

Well, first of all you probably should use time-steps so your movements aren't frame dependent. (Just multiply all your speeds for moving/rotation etc with how long it took to loop through one frame in seconds using the irrlichtdevice->getTimer()->getTime(), in case you didn't know that). This should make all movements stable and the same EXCEPT you'll still have frame-rate issues, of which, I'm not sure what it could possibly be.

My first idea was that recv() was blocking, but then I read that you turned off blocking. It's quite odd seeming as I've used winsock in some of my tests and demos and it's all worked perfectly fine.

[LunaRebirth]

Well, even if I don't do coordinates or rotations being sent/recvd.
If it's something simple like

Code: Select all

int RecvTheNumberOne;
recv(sock,(char*)&RecvTheNumberOne,sizeof(int),NULL);

It still really slows the program down for anyone who is not the host.

I tried doing like Tutorial 4 and making everything update by timer (in case of low FPS) but for anyone who is not on the same computer as the server bugs out (Like walking really quick and then stopping multiple times per second) which is quite annoying.

Edit:
Sorry Ruxify, just re-read your reply and I didn't understand correctly. Paragraph 1 was off topic, but paragraph 2 should answer that I did try that. (But again, it's buggy so I'm trying to stay away from it for now)

[mongoose7]

You may be sending huge amounts of data, which wouldn't be so noticeable locally. You may also be Nagled to death. Try to send less data. Have the client anticipate as much as possible and have the server confirm.

[LunaRebirth]

I got it worked out.
Changed the camera to also update to node position to timeframe. (Using Tutorial4's method) and the character looks like he moves quickly and smoothly (Even with low FPS).
It worked, and so it looks normal now for everyone.

Also, how much is "huge amounts of data"? Because I'm sending (double)PlayerX,Y,Z (double)PlayerRotationX,Y,Z and (double)PlayerID (7 doubles total)

[mongoose7]

Do you send the data in one packet? If you send it in three packets you will be hit by the Nagle algorithm. Actually, you should only call send() once per frame (or less).

Also, you can check the network I/O and CPU utilisation on the server.

[thanhle]

7 double is not much.
When you get slowdown. Maybe you can use the prediction method so that the motion of the character is continuous.
E.g. If the character move in a certain direction then send the direction once, then use prediction method on clientside to predict where the character is on the next frame or so. Overwrite prediction with actual when other character change direction etc. That will likely optimise the packet transfer rate.

[REDDemon]

I assume your socket is blocking(waiting response packet: on my connection that will take hundreds milliseconds) and you need it to be unblocking (return immediatly, you have to poll it everyframe)?