During each tick, the server processes incoming user commands, runs a physical simulation step, checks the game rules, and updates all object states. After simulating a tick, the server decides if any client needs a world update and takes a snapshot of the current world state if necessary. A higher tickrate increases the simulation precision, but also requires more CPU power and available bandwidth on both server and client.
HLDS
Half Life Dedicated Server. The program you should be running and trying to optimise if you are here.
FPS
Frames per Second.
Client FPS
Is the number of times per second the game checks for inputs, either from keyboard/mouse and incoming game packets, basically any I/O operation.
Server FPS
Because there are no keyboard or mouse I/O's occurring, it only deals with how often the server checks for game packets.
fps_max
Sets an upper limit on the frames per second the server runs at. Default=300
sv_maxrate
The Maximum amount of data in Bytes per Second the server will send to the client. Conversely, the Maximum amount of data in Bytes per Second the Client can request from the Server. sv_maxrate overrides the clients rate setting if sv_maxrate is less than the clients rate setting. Default=0 Maximum=30000
sv_minrate
The Minimum amount of data in Bytes per Second the server will send to the client. Conversely, the Minimum amount of data in Bytes per Second the Client can request from the Server. sv_minrate overrides the clients rate setting if sv_minrate is greater than the clients rate setting. Default=0
sv_maxupdaterate
The Maximum amount of Update per Second the server will send to the client. Conversely, the Maximum amount of Updates per Second the Client can request from the Server. sv_maxupdaterate overrides the clients cl_updaterate setting if sv_maxupdaterate is less than the clients cl_updaterate setting. Default=60
sv_minupdaterate
The Minimum amount of Update per Second the server will send to the client. Conversely, the Minimum amount of Updates per Second the Client can request from the Server. sv_minupdaterate overrides the clients cl_updaterate setting if sv_minupdaterate is greater than the clients cl_updaterate setting. Default=0
rate
The Maximum amount of Bytes Per Second the Client will request from the server. rate overrides the servers sv_maxrate setting if rate is less than the servers sv_maxrate setting. Default=(Depends Upon Clients STEAM Internet Connection Setting) Maximum=30000
cl_updaterate
The Maximum amount of Updates Per Second the Client will request from the server. cl_updaterate overrides the servers sv_maxupdaterate setting if cl_updaterate is less than the servers sv_maxupdaterate setting. Default=20
cl_cmdrate
The Maximum amount of Updates Per Second the Client will Send to the server. Default=30 Minimum=10 Maximum=100
NB: sv_maxupdaterate and cl_updaterate cannot cause more data to be sent to the client than the sv_maxrate and rate settings allow, or the servers, or most likely the clients actual available bandwidth allows. Choke occurs when either;
The servers sv_maxupdaterate causes the amount of bandwidth to exceed the bandwidth allocated per client by sv_maxrate or the total amount of bandwidth the server has access to,
The clients cl_updaterate causes the amount of bandwidth required by the client to exceed the clients rate setting or the total amount of bandwith the client has access to.
Server Rates
Tickrate is set by adding the -tickrate 100 (for a tickrate 100 server) in the command line start up parameters. Tickrate cannot be changed on the fly via console, HLSW or rcon, it can only be changed in the commandline and the server must be restarted for the change to take effect.
If you want your tickrate changes to have any noticeable benefit you must change a few other server variables as well as change the Windows Kernel Timer Resolution (pingboosting)
To change the Windows Kernel Timer Resolution (pingboost a server) all you need to do is run Windows Media Player. It does not need a file open, it just has be running in the background, if you do not do this, your servers fps will be limited to around 64 frames a second.
The servers fps can be seen by issuing the stats command in console or via HLSW or via the RCON STATS if you are logged in via rcon on the server. The server fps is regulated by the fps_max command (default is 300) which ends up producing around 256 fps in RCON STATS. Don't ask me why, I've asked Valve, but the next step up is to run your fps_max at 600 so you then get 512 fps in RCON STATS. It can be set somewhere between 512 and 600 via console or HLSW and permanently by adding the commandline parameter +fps_max 600, but if you set it at 511 or lower you will see that your FPS according to RCON STATS will still sit at 256 fps even after a map change, so you must set your fps_max higher than what you actually want, to achieve the desired affect. fps_max 512 produces strange results on ping boosted Windows based HLDS, where as fps_max changes on Linux HLDS is affected by many variables, such as, Kernel Version, Kernel Timer, and Hardware so the rules for fps_max that apply to Windows HLDS has minimal relevance to Linus HLDS. DO NOT take my word for it, test it yourself! The reason for running a high server fps, is to ensure that when a server does run a tickrate calculation, that it is using the most up to date information available.
So you have a high tickrate, your server is pingboosted and is running at high fps, none of this is of any use to your clients (the players) if you do not change your servers rates, specifically the sv_maxrate and sv_maxupdaterate variables.
sv_maxrate (default is 0, maximum = 30,000 ). I personally have found that the sv_maxrate 0 setting is detrimental to server performance (purely subjective opinion, but there you go, feel free to ignore it until your clients start complaining about stupid lag and player warping issues that don't correlate to any actual network or cpu usage or over usage issues as the case may be) then set your sv_maxrate to 20000 or if you have player numbers in excess of 20 use sv_maxrate 30,000
sv_maxupdaterate (default 60) setting must be changed to start using all this server generated data more effectively and get the data out to your players who want to run 101/101/20000/10000 cl_cmdrate/cl_updaterate/rate/cl_rate (yes I know cl_rate is defunct but some people can't be told so I humour them and leave it in) settings, thus you need to change your sv_maxupdaterate equal the tickrate. You only have to do this if you run a tickrate higher than 50. eg for tickrate 66 run sv_maxupdaterate 66 or even 100, for tickrate 100 run sv_maxupdaterate 100. If you do not do this, your clients will NEVER see the full benefit of your tickrate changes, and even then, because of server load the clients will not see the full sv_maxupdaterate or tickrate reflected in a net_graph 3. (See below for more information about net_graph 3)
Do not run tickrate higher than 1000 with pingboost on, Valve have admitted that there will be issues if you push the tickrate too high. In fact as of 09January2006 players will have problems on 1000 tickrate servers with pingboost option 3, with doors that won't open and get stuck in spots that will not get them stuck on 66 tickrate servers, e.g. Crouched hard up against boxes on angles.
Make sure you have the bandwidth and CPU to cope with HLDS running with these settings. If you don't have at least a 10Mbps Full Duplex link , you probably do not have the bandwidth to see the full benefit of following the above instructions. This is aimed at people with servers in dedicated data centres with appropriate high speed Internet connections. Most home users will not have the necessary bandwidth or hardware to take full advantage of ALL of these settings. You may though be able to increase your end users overall experience, just by pingboosting your server and increasing the tickrate and fps_max whilst leaving the sv_maxrate and sv_maxupdate rate settings low.
24, 32 & 40 player servers should be run with a tickrate of no more than 66 and sv_maxupdaterate of 100. I've tried higher but you get strange issues for the clients if you do. Well you can if you want, but you need A LOT of CPU dedicated to a single HLDS process.
The fps_max setting of 600 does not appear to hit the CPU as hard as other settings I have mentioned here do, your mileage may vary, but try reducing this back to default of 300 if your clients get strange lag issues and you have tried reducing the other server variables mentioned here. i.e. Change this one last! NB: Your servers fps will not exceed the kernel timer resolution, which varies depending upon what Operating System is being run and how it is setup.
For competition servers, or any server at the 18 player or less mark, then you should be able to use a tickrate of 100 and an sv_maxupdaterate of 100 successfully without any issues, so long as you have the bandwidth and CPU to cope!
For changes to take affect, the settings must be changed in the server.cfg file (except tickrate & fps_max which should be command line variables) and the server restarted, or if done via RCON, a map change must be done.
This was written on the basis that your HLDS is a default HLDS Installation with no Mods/Plugins or Non-Standard anything else, such as sounds, skins, maps etc on the server. Using them (Mods/Plugins) will increase CPU utilisation and thus limit the final result. Obviously you need to monitor these for your particular situation.
Finally, you need to actually play on your server for several hours with all HLDS processes full to see if there are any issues that do not show up by normal performance monitoring tools, to ensure everything is running ok. Subjective in game experience can deviate significantly from Objective Server Statistics, thus you will not know there is a problem unless you are on the server playing at the time it happens.
Client Rates
Clients must have their STEAM Internet Connection Settings setup correctly for their Internet connection.
The clients rate should = the servers sv_maxrate
The clients cl_updaterate should = the servers sv_maxupdaterate which equals the servers tickrate
Thus a server with sv_maxrate 20000 tickrate 100 sv_maupdaterate 100 the clients though run the following settings:
- rate 20000
- cl_updaterate 100
- cl_cmdrate 100
- cl_interpolate 1
- cl_interp 0.1
- cl_smooth 0
These settings will provide the best client experience so long as your server & network can cope with running with a high tickrate and the rates required to take advantage of them.
NB: If your server settings are different to the example just mentioned, your client settings will have to change accordingly. This is just an example, do not think that these rates are optimum for all server settings, they are not, and your optimum client settings will need to change accordingly.
Summary
<> 20 Player servers
-tickrate 66
sv_maxrate 20000
sv_maxupdaterate 66
fps_max 600
Make sure you have the CPU and bandwidth to cope
What you need to look out for is high CPU usage on the server and/or choke on clients that did not get it before you made changes to your servers tickrate and associated settings, and/or fps that running constantly well below the Kernel Timer and/or below the tickrate. Or otherwise, just blatanly obvious crap lag on the server to put it bluntly.
i.e. If you run at 66 tickrate with 50% CPU and 1000 tickrate at 90% CPU then its obvious that 66 tickrate is what you are going to have to run your server at.
If you set your kernel timer to 500Hz or there abouts, and fps_max at 600, but your server is only getting 150-200 fps constantly, then its obvious you need to change the kernel timer and/ore the fps_max to a lower setting.
