Parameters That Control System Performance

The following parameters control various aspects of system performance:

Parameter	Description
`fs.file-max`	Specifies the maximum number of open files for all processes. Increase the value of this parameter if you see messages about running out of file handles.
`kernel.io_uring_disabled`	Specifies the disabled setting for creating `io_uring` instances. `io_uring` provides an interface to handle asynchronous I/O operations that can improve performance for storage and networking. `io_uring` is supported with UEK and is enabled by default when running UEK on Oracle Linux. You can set the following values for the `io_uring` parameter: `kernel.io_uring_disabled`=0 (default). This setting specifies all processes can create `io_uring` instances. `kernel.io_uring_disabled`=1. This setting specifies only processes with `CAP_SYS_ADMIN` privileges can create `io_uring` instances. `kernel.io_uring_disabled`=2. This setting specifies that `io_uring` instance creation is disabled for all users.
`net.core.netdev_max_backlog`	Specifies the size of the receiver backlog queue, which is used if an interface receives packets faster than the kernel can process them. If this queue is too small, packets are lost at the receiver, rather than on the network.
`net.core.rmem_max`	Specifies the maximum read socket buffer size. To minimize network packet loss, this buffer must be large enough to handle incoming network packets.
`net.core.wmem_max`	Specifies the maximum write socket buffer size. To minimize network packet loss, this buffer must be large enough to handle outgoing network packets.
`net.ipv4.tcp_available_congestion_control`	Displays the TCP congestion avoidance algorithms that are available for use. Use the `modprobe` command if you need to load additional modules such as `tcp_htcp` to implement the `htcp` algorithm.
`net.ipv4.tcp_congestion_control`	Specifies which TCP congestion avoidance algorithm is used.
`net.ipv4.tcp_max_syn_backlog`	Specifies the number of outstanding `SYN` requests that are allowed. Increase the value of this parameter if you see `synflood` warnings in the logs that are caused by the server being overloaded by legitimate connection attempts.
`net.ipv4.tcp_rmem`	Specifies minimum, default, and maximum receive buffer sizes that are used for a TCP socket. The maximum value can't be larger than `net.core.rmem_max`.
`net.ipv4.tcp_wmem`	Specifies minimum, default, and maximum send buffer sizes that are used for a TCP socket. The maximum value can't be larger than `net.core.wmem_max`.
`vm.swappiness`	Specifies how likely the kernel is to write loaded pages to swap rather than drop pages from the system page cache. When set to 0, swapping only occurs to avoid an out of memory condition. When set to 100, the kernel swaps aggressively. For a desktop system, setting a lower value can improve system responsiveness by decreasing latency. The default value is 60. Caution: This parameter is intended for use with laptop computers to reduce power consumption by the hard disk. Don't adjust this value on server systems.