Welcome to

OpenOnload® is a high performance network stack from Solarflare that dramatically reduces latency and cpu utilisation, and increases message rate and bandwidth. OpenOnload runs on Linux and supports TCP/UDP/IP network protocols with the standard BSD sockets API, and requires no modifications to applications to use. It achieves performance improvements in part by performing network processing at user-level, bypassing the OS kernel entirely on the data path. Networking performance is improved without sacrificing the security and multiplexing functions that the OS kernel normally provides.

OpenOnload is available as a free download from the Solarflare support site.

Google TechTalk
In February 2008 we gave a tech-talk at Google all about the implementation of OpenOnload. Watch here, and the slides are here.


OpenOnload comprises a user-level shared library that intercepts network-related system calls and implements the protocol stack, and supporting kernel modules. It is compatible with the full system call API, including those aspects that usually problematic for user-level networking, such as fork(), exec(), passing sockets through Unix domain sockets, and advancing the protocol when the application is not scheduled.

OpenOnload is compatible with at least the following Solarflare network adapters:

OpenOnload contains algorithms and uses hardware interface techniques which are subject to Solarflare Communications, Inc. patent applications. Parties interested in licensing Solarflare's IP are encouraged to contact Solarflare's Intellectual Property Licensing Group at:

Director of Intellectual Property Licensing
Intellectual Property Licensing Group
Solarflare Communications, Inc.
7505 Irvine Center Drive Suite 100
Irvine, California 92618

A list of patents associated with these products can be found at: https://www.solarflare.com/patent.


EnterpriseOnload is a subscription-based version of OpenOnload that includes a support contract. Benefits include:


For help using OpenOnload and to report bugs or suggest improvements; please email Solarflare's support team: support@solarflare.com.

Solarflare offers support contracts with guaranteed service level agreements. Please contact the Solarflare sales team for more information.