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KGS lag (yes, another thread like this)
http://www.lifein19x19.com/viewtopic.php?f=24&t=7541		 Page 1 of 1
Author:  mhlepore [ Tue Jan 01, 2013 4:30 pm ]
Post subject:  KGS lag (yes, another thread like this)
I have experienced significant lag on my mac for I am guessing the last six to nine months. Others seem to have also experienced this. Before I get the normal responses (there is no lag, you need to fix your wireless router, just play longer games), let me say the following:

- My lag tends to get worse over the course of the game. I regularly lose games with 20 minutes of main time and 5x30 byoyomi.
- Maybe I am just hallucinating, but when I get into a web browser and change the website, it seems to "wake up" KGS and make my move for me. This stops working after we get far enough into the game (if it is actually occurring in the first place).
- My wife and I each have a macbook pro. She plays on her computer, using the same wireless router, without incident. When I get on her machine and play I am fine.
- I have looked at old threads and done a traceroute command as some suggest. My wife's computer takes a different route to gokgs.com than mine, but my route does not seem to be hopping to places that are obviously delaying transmission.
- I have downloaded the latest java version, with no apparent benefit.

Bottom line is online Go is no longer fun - If I don't lose by timing out I will lose by rushing through the middle game/early endgame out of fear of timing out. Any thoughts? Not looking for trolls, flames, etc. - just want suggestions. Thanks!
Author:  speedchase [ Tue Jan 01, 2013 4:31 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
The fact that your wife's computer works fine and yours doesn't suggests that they are connecting differently. I would recommend checking to make sure that they use the same network.
Author:  xed_over [ Tue Jan 01, 2013 7:46 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
speedchase wrote:
The fact that your wife's computer works fine and yours doesn't suggests that they are connecting differently. I would recommend checking to make sure that they use the same network.

Not necessarily. I've experienced the same thing mhlepore is reporting. Using multiple laptops to connect from the same home network, one seem to work flawlessly, while the other has tremendous lag issues. And sometimes one machine might be Windows, and another Mac, or the other way around, or both Mac or both Windows, etc. There is an issue, and its been around for years, and its not a simple one to debug.
Author:  ez4u [ Tue Jan 01, 2013 7:58 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
Traceroute is not really to the point IMHO. I think the starting point is rather logging some activity through tcpdump and analyzing it. Do you have real delays in the communication activity between KGS and yourself? If so, how does it compare to the activity shown between KGS and your wife's machine? If not, can you track down some specific moves where you observe a delay and know that it was not due to the link? That implies that there is a delay in the client response, etc.

I was playing with windump (tcpdump for windows PCs) a few months ago along these lines. I could document from the log files that in my case there were no significant communication delays when playing. I could also determine that there was no difference between the tcp communications and the time stamps in the game files for moves. I never got around to the next step of comparing observed delays on screen to the communication sequence in the log file, since I was not having a big problem at that time and the process for doing so is not so straight forward (basically you have to use a screen capture program or keep careful, manual notes while playing).
Author:  mhlepore [ Tue Jan 01, 2013 8:14 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
Thanks to those who have responded. I can confirm that both my wife and I are using the same wireless network connection. What ez4u has in mind with tcpdump seems over my head and I would not know where to start.
Author:  xed_over [ Tue Jan 01, 2013 10:42 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
Yeah, I don't think tcpdump is the issue. I don't even think its a network communication issue. I suspect is a local memory/resource issue, and possible thread lock condition within the local client. To prove that would take more even more complicated debugging using strace, etc.

I'm a big fan of Macs, but I think their memory management is the worst design ever. I'm constantly getting the spinning color wheel of death just waiting for my browser to wake up -- I never close any apps, have hundreds of browser tabs open, and haven't rebooted for months at a time (my current uptime is 371 days).

Java programs can be a bit of a memory hog too.

Giving CGoban more than the default 150m would might help with the lag issue, but its defined in the jnlp (http://files.gokgs.com/javaBin/cgoban.jnlp), so the only way I know to modify the value would be to manually download and run the jar, and for the average user that would be tedious at best.
Author:  Pippen [ Thu Jan 10, 2013 6:15 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
Here's an odd thing that happens often to me lately. I play and made my move. The time from my opponent is running...and running out...then all of a sudden it says that I lost on time. I mean it's on thing if you lose connection or have lag, another that it's me that loses. Did that ever happen to someone?
Author:  xed_over [ Fri Jan 11, 2013 7:43 am ]
Post subject:  Re: KGS lag (yes, another thread like this)
Pippen wrote:
Here's an odd thing that happens often to me lately. I play and made my move. The time from my opponent is running...and running out...then all of a sudden it says that I lost on time. I mean it's on thing if you lose connection or have lag, another that it's me that loses. Did that ever happen to someone?

Yes, that's a common problem with lag.

The problem is your local client is lagging, so it hasn't yet seen your opponent's move from the server. So your opponent's clock is still running down locally, but on the server, your opponent has already made his move, so your clock is actually running down on the server (only you can't see it).

When the client and server finally re-synchronize, its too late. You've lost on time (even though it looked from your side initially that your opponent lost on time).

So, if you have known lag issues, be sure have long enough time settings to not run out of time.
Author:  Pippen [ Fri Jan 11, 2013 10:33 am ]
Post subject:  Re: KGS lag (yes, another thread like this)
@xed-over: Can one fix this problem with lag or can one see when the lag hits? Because in my case only sometimes my connection is laggy, in 85% my moves are made instantly.
Author:  xed_over [ Fri Jan 11, 2013 11:21 am ]
Post subject:  Re: KGS lag (yes, another thread like this)
Pippen wrote:
@xed-over: Can one fix this problem with lag or can one see when the lag hits? Because in my case only sometimes my connection is laggy, in 85% my moves are made instantly.

Not sure.

I usually try typing into the chat window if I suspect lag. It may not "wake it up", but it can confirm you're having an issue. I don't know if temporarily "escaping" the game by closing the window will tell the server to reset your clock or not. Perhaps some experimentation is in order.

For myself, I usually experience the problem the most when on a wireless connection, and switching to a wired connection usually solves the issue (and I've had experience managing a dozen or more clients doing game recording at tournaments).

Wireless networking can be problematic anyway depending on how much other wireless traffic is in the area and overlapping frequencies, etc. Also how far away from the router, and how many other devices are sharing the same wireless network.

Wired connections are not totally immune either, but far more reliable.
Author:  nascent [ Thu Jan 24, 2013 2:46 pm ]
Post subject:  Re: KGS lag (yes, another thread like this)
THat yours and your wife's computers are similarly connected, but do not share the problem leads me to guess that there is a difference in your network settings.

That the traceroute results are different for two computers using the same gateway tells me that the difference is either in the "default packet size", the "maximum transmission unit", or the "do not fragment" flag.

It is highly unlikely that the tracerout differences are due to different routing options, because most hosts (and many routers) automatically drop any source routed frames.

I would check your network settings against those on your wife's computer, and set yours to match the better performing machine.

Of course, it may be something else entirely.

Good luck,

--nascent--
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