[ASIO] design question, multiple listenning sockets vs. one
Hello, I am creating a SIP load tester. The load tester will mimic thousands of SIP end-points registering and making phone calls to a SIP proxy. Originally I have created one udp::socket object for each mimic'd SIP end-point. Each listening and executing async_receive_from() on its own port. So if I have 1000 SIP end-points, I have 1000 udp::sockets listening, receiving, and writing. I am expecting to go up to 20,000 SIP end-points in production. The reason I did this is because when packets arrive to the udp::sockets, I know exactly which SIP end-point it belongs to... which saves the app the hassle of having to parse through the new SIP packet to figure out which SIP end-point it should go through. But I did not take into account any back-end context switching that boost::asio::io_service might be doing or other overhead it might do. I cannot find much information about this. The alternative would be to have one udp::socket (or maybe a few, one on its own thread for example) and parse the incoming packets to figure out which SIP end-point it belongs to. So this comes down to parsing incoming SIP messages and using one (or a few) udp::sockets on its (their) own thread, versus using many udp::sockets but no SIP message parsing. Does anyone have any insight into the back-end context switching that boost::asio uses to work its magic? Does 20,000 udp::sockets each listenning and receiving scream out 'NO DO NOT DO THIS'? Any insight is welcomed. thanks jose
If you are running this on a recent version of Linux then the epoll(2) syscall that is applied by the io_service object should be able to handle that many sockets. It is only down to what amount of open file descriptors you are allowed on a per process level that could hamper the aim of 20,000 sockets. I would rather have been using a single socket, since SIP is UDP based to circumvent the issue. If you could increase your receiving buffer in the OS for that socket then there should be no issue and you can go up to the equivalent of 30,000 - 40,000 connections. (sockopt(2)). This is just what I would have done.
Just for reference. The high performance game networking library (very low level type access, yet very high level creation, very well made) RakNet, has successfully had over 100,000 connections at once (admittedly, most are idle, just a 'ping' every thirty second to keep the connection active). It is pure UDP based, and yet it is reliable. This is all on only one port, hence, one port is the best design to go with, there are a great deal of examples out there that prove this.
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Etienne Philip Pretorius -
Jose Martinez -
OvermindDL1