-threads 1: What does it do?

[Patriot]

Hi Edge100x,

Many times on these forums you have recommend that we include -threads (1, 3, ?) in our server command lines. In particular for L4D2 and CSS, but for other source games as well.

What exactly does this command do and why is it important to the performance of our game servers?

I've searched all over the web and cannot find any real documentation on the -threads command. There are some discussions about it, but they are mostly speculation. You obviously have some knowledge of and confidence in this command, otherwise you would not recommend it to your customers.

Please share what you know about it.

Thank you,

Patriot

[Edge100x]

Valve hasn't documented it well to us, either. It clearly has something to do with how their game handles multithreading, but beyond that, I'm not sure what it does. It might restrict the server to only using one thread overall, or it might mean that it only uses one thread in addition to its primary thread, for instance.

Valve employees have recommended setting -threads 1 to us for several problems, including L4D2 map changes timing out, TF2 random lag events, and CS:GO not starting up correctly on large machines (such as our 32-HT-core dual E5-269 boxes).