TCP performance re-visited

Detailed measurements and analyses for the Linux-2.4 TCP stack on current adapters and processors are presented. We describe the impact of CPU scaling and memory bus loading on TCP performance. As CPU speeds outstrip I/O and memory speeds, many generally accepted notions of TCP performance begin to unravel. In-depth examinations and explanations of previously held TCP performance truths are provided, and we expose cases where these assumptions and rules of thumb no longer hold in modernday implementations. We conclude that unless major architectural changes are adopted, we would be hard-pressed to continue relying on the 1GHz/1Gbps rule of thumb.