An Efficient Packet Sending Method for Paravirtualized Network Cards

Abstract

The invention discloses a data packet efficient transmitting method for a para-virtualized network interface card. Learning from the design of Linux NAPI, when I / O threads process a transmitting queue, a notification mode and a polling mode are automatically switched according to the frequency of transmitting data packets by a client, wherein if the frequency of transmitting the data packets by the client is larger than a certain threshold value, polling continues to detect whether data in the transmitting queue needs to be processed or not, a notification mechanism of the client is kept in a stopped state, and the number of VM Exits is reduced; if the frequency of transmitting the data packets by the client is smaller than a certain threshold value, the polling mode is withdrawn, the notification mechanism of the client is started, the client waits for being awakened next time, and waste of CPU resources is reduced. The two I / O thread process the transmitting queue and a receiving queue respectively, the two I / O threads operate on the same physical core, the fairness between the two I / O threads is guaranteed by a CFS dispatcher, and the CFS dispatcher can achieve fair dispatching according to the operating time and sleep time of the threads.

Description

technical field [0001] The invention relates to the field of system network I / O virtualization and semi-virtualized network cards, in particular to a method for efficiently sending data packets for the semi-virtualized network card. Background technique [0002] The paravirtualized network card technology modifies the client operating system to make it aware that it is in a virtualized environment, so that it can cooperate with the VMM to greatly improve network I / O performance. In contrast, although the traditional fully virtualized network card has high flexibility and compatibility, the path of each I / O operation is too long, there are more VM Entry and VMExit, and it needs to be processed multiple times. Context switching and data copying, poorer performance. Therefore, paravirtualized network cards have become one of the current mainstream I / O virtualization technologies, and are widely used in network deployment of virtual machines. [0003] Paravirtualization usuall...

AI Technical Summary

Problems solved by technology

Therefore, when the client uses the paravirtualized network card to send data packets to the outside world, a large number of VM Exits will be generated, which will affect the I / O response delay and network throughput.

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