Large receive offload
Encyclopedia
In computer network
ing, large receive offload is a technique for increasing inbound throughput
of high-bandwidth
network connections by reducing CPU
overhead. It works by aggregating multiple incoming packets from a single stream into a larger buffer before they are passed higher up the networking stack, thus reducing the number of packets that have to be processed. In Linux
, it is generally used in conjunction with the New API
(NAPI) to also reduce the number of interrupt
s.
According to benchmarks, even implementing this technique entirely in software can increase network performance significantly. As of April 2007, the Linux kernel
supports LRO for TCP
in software only. FreeBSD-8 supports LRO in hardware on adapters that support it.
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
ing, large receive offload is a technique for increasing inbound throughput
Throughput
In communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. This data may be delivered over a physical or logical link, or pass through a certain network node...
of high-bandwidth
Bandwidth (computing)
In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...
network connections by reducing CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
overhead. It works by aggregating multiple incoming packets from a single stream into a larger buffer before they are passed higher up the networking stack, thus reducing the number of packets that have to be processed. In Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
, it is generally used in conjunction with the New API
New API
New API is an interface to use interrupt mitigation techniques for networking devices in the Linux kernel.Such an approach is intended to reduce the overhead of packet receiving...
(NAPI) to also reduce the number of interrupt
Interrupt
In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
s.
According to benchmarks, even implementing this technique entirely in software can increase network performance significantly. As of April 2007, the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
supports LRO for TCP
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
in software only. FreeBSD-8 supports LRO in hardware on adapters that support it.