Player join/leave lag

[Pazuzu]

Hi,

I am running a 100tick srcds server for CS:S on a Fedora Core 4 box, spec:

Intel Celeron 2.66GHz
512MB RAM
10mbit unmetered network connection

The server is capped to 12 players, and there's normally around 8 players on it. The problem I'm having is that regardless of player count, everyone playing gets a lag spike whenever a player joins or leaves. It's twice as bad when someone rejoins, because there are 2 lag spikes in quick succession. I was wondering whether anything could be done about it. I'm thinking that the bottleneck in the machine spec is the RAM. Frustratingly the server runs smoothly except for the join/leave lag, so my guess is it lags when srcds swaps out memory so it can allocate more for the the newly joining player.

Any thoughts, or commands that you know of that might help to calm the spikes?

[Muppet]

Sounds suspicious - but those specs *shouldn't* be causing that much problem. Do you run a custom kernel for >100fps server side? If not, you could recompile a 1000hz kernel and see what happens.

Might be an idea to try a full format of the HD and reinstall the OS with a vanilla kernel and see if the same problem occurs. If the problem still occurs, you could even try another kernel and if that fails.. then would probably need to update hardware.

But, those specs that you mentioned, shouldn't be causing lag spikes like that. I had a 2ghz P4 a while ago, same amount of ram with a 100mb unmetered line - no lag spikes.

[Pazuzu]

Thanks for the reply.

Unfortunately it's not my machine so I'm unable to reformat. Is there anything I can do to srcds specifically, commands, or uninstalling and re-installing using hldsupdatetool maybe?

And I forgot, here's the kernel version:
Linux version 2.6.18-1.2869.fc6 (brewbuilder@hs20-bc1-7.build.redhat.com) (gcc version 4.1.1 20061011 (Red Hat 4.1.1-30)) #1 SMP Wed Dec 20 14:51:46 EST 2006

[Muppet]

You could try a fresh install of srcds with no plugins. I doubt theres any commands you could enter in srcds to help with this problem.

Trying running the server 66 tick and see if the problem still occurs (just to rule out if -tickrate 100 being a problem on your machine)

[Pazuzu]

Ok I'll try a reinstall of srcds.

Thanks for your speedy help

[Muppet]

Seems other people have been getting lag spikes with the 2.6.18 kernel (although not truely confirmed - just specualtion). They have said that downgrading to 2.6.8 or even 2.5.6 has sorted the problem for them.

The issue has only occurred recently (in the last few updates) so you could just wait it out and see as there has just been a new beta released which should hopefully sort all these problems.

[nix]

Hi
Try to writhe top in a console and post it here.

[Pazuzu]

The CPU load is OK, if that's what you wanted to know. It reaches about 30% with 6 players, and doesn't seem to go over 50% even with 12.

[Pazuzu]

Muppet Wrote:Seems other people have been getting lag spikes with the 2.6.18 kernel (although not truely confirmed - just specualtion). They have said that downgrading to 2.6.8 or even 2.5.6 has sorted the problem for them.

The issue has only occurred recently (in the last few updates) so you could just wait it out and see as there has just been a new beta released which should hopefully sort all these problems.

Yeah, it does seem to have come around recently - getting worse in the last week or so. I think I'll take your advice and wait till the next release to see if it's fixed before I do anything drastic.

[nix]

it was the load on the ram i want to know.

[Muppet]

top is a bad way to view memory usage on a linux system. Linux, by default, uses up as much ram as possible (but most of this actually acts as cache therefore not true representation of usage).

One way i've found is to type 'free' into a terminal:

Code:

total       used       free     shared    buffers     cached

Mem:        514508     508384       6124          0        728     295456

-/+ buffers/cache:     212200     302308

Swap:       995988     230280     765708

Then to check your ram usage, look at Mem section and take away the cached amount from the free. On this it would be 508384 - 295456 = ~208MB ram used.

[nix]

here is a dump of my server when i use top

top - 19:46:28 up 4 min, 2 users, load average: 0.08, 0.13, 0.06
Tasks: 77 total, 1 running, 76 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0% us, 0.2% sy, 0.0% ni, 99.8% id, 0.0% wa, 0.0% hi, 0.0% si
Mem: 2065256k total, 241192k used, 1824064k free, 27548k buffers
Swap: 2031608k total, 0k used, 2031608k free, 108692k cached

[Pazuzu]

Code:

total       used       free     shared    buffers     cached
Mem:        506328     500180       6148          0       2328     173256
-/+ buffers/cache:     324596     181732
Swap:       522072     160216     361856

So that's 500180 - 173256 = 326924 = ~319MB ?
(And that's with 7 people on the server)

And from top:

top - 19:15:53 up 3 days, 10:43, 1 user, load average: 0.77, 0.65, 0.47
Tasks: 132 total, 4 running, 128 sleeping, 0 stopped, 0 zombie
Cpu(s): 15.9%us, 1.7%sy, 0.0%ni, 80.1%id, 0.7%wa, 0.0%hi, 1.7%si, 0.0%st
Mem: 506328k total, 500096k used, 6232k free, 2100k buffers
Swap: 522072k total, 160216k used, 361856k free, 172908k cached

[Muppet]

Aye, 319mb sounds about right on 512MB ram. I wouldn't think it would jump much higher with 12 people on, certainly not above 512MB where virtual memory would be used.

Can only be kernel/OS related or this srcds bug as far as i can see.

[nix]

i had the same when i was running fc 4 ,it eats up a lot of swap memory.
and i think that's why the lag spikes.