What threads does swoole have?

Threads in swoole:

1. MainReactor (main thread)

The main thread will be responsible for monitoring the server socket. If a new connection is accepted, the main thread will evaluate the number of connections for each Reactor thread. Assign this connection to the reactor thread with the smallest number of connections to perform load balancing.

2. Reactor thread group

The Reactor thread is responsible for maintaining the TCP connection of the client machine, processing network IO, and sending and receiving data in a completely asynchronous and non-blocking mode.

After accepting a new connection, swoole's main thread will assign the connection to a fixed Reactor thread, read the data when the socket is readable, perform protocol analysis, and deliver the request to the Worker process. Send data to the TCP client when the socket is writable.

3. Heartbeat packet detection thread (HeartbeatCheck)

After Swoole configures heartbeat detection, the heartbeat packet thread will check all previously online connections within a fixed period of time

Send detection data packet

4. UDP packet receiving thread (UdpRecv)

Receive and process client udp data packet

swoole To achieve the best performance, multiple worker processes must be created to help process tasks, but the Worker process must be forked. However, the fork operation is unsafe. If there is no management, many zombie processes will appear, which will affect server performance. At the same time, The worker process is accidentally killed or exits abnormally due to program reasons. In order to ensure the stability of the service, the worker process needs to be re-created.

Recommended learning: swoole video tutorial

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