netipv4tcp_rmem

net.ipv4.tcp_rmem is a Linux kernel parameter that defines the minimum, default, and maximum values of the receive buffer space (in bytes) for TCP sockets. It is used to control the amount of memory that can be allocated by the kernel to receive data from a TCP connection.

The parameter takes three values, separated by commas, in the format of min:default:max. The "min" value represents the minimum size of the receive buffer in bytes, "default" represents the default size of the buffer, and "max" represents the maximum size of the buffer.

For example, if the value of net.ipv4.tcp_rmem is set to "4096 87380 6291456", it means that the minimum receive buffer size is 4KB, the default size is 87,380 bytes, and the maximum size is 6,291,456 bytes.

Adjusting these values can help optimize TCP performance based on the network conditions and the application requirements. For example, increasing the default value may improve the throughput of large file transfers, while decreasing it may reduce latency for interactive applications