Application performance pitfalls and TCP's Nagle algorithm

Abstract

Performance improvements to networked applications can have unintended consequences. In a study of the performance of the Network News Transport Protocol (NNTP), the initial results suggested it would be useful to disable TCP's Nagle algorithm for this application. Doing so significantly improved latencies. However, closer observation revealed that with the Nagle algorithm disabled, the application was transmitting an order of magnitude more packets. We found that proper application buffer management significantly improves performance, but that the Nagle algorithm still slightly increases mean latency. We suggest that modifying the Nagle algorithm would eliminate this cost.