This is one ancient problem. I remember dealing with it in 2003. Writeup from 1997 here (P-HTTP basically means HTTP version 1.1): https://www.isi.edu/~johnh

This is one ancient problem. I remember dealing with it in 2003. Writeup from 1997 here (P-HTTP basically means HTTP version 1.1): https://www.isi.edu/~johnh/PAPERS/Heidemann97a.html https://www.isi.edu/~johnh/PAPERS/Heidemann97a.html > John Heidemann. Performance Interactions Between P-HTTP and TCP Implementations. ACM Computer Communication Review. 27, 2 (Apr. 1997), 65–73. > This document describes several performance problems resulting from interactions between implementations of persistent-HTTP (P-HTTP) and TCP. Two of these problems tie P-HTTP performance to TCP delayed-acknowledgments, thus adding up to 200ms to each P-HTTP transaction. A third results in multiple slow-starts per TCP connection. Unresolved, these problems result in P-HTTP transactions which are 14 times slower than standard HTTP and 20 times slower than potential P-HTTP over a 10 Mb/s Ethernet. We describe each problem and potential solutions. After implementing our solutions to two of the problems, we observe that P-HTTP performs better than HTTP on a local Ethernet. Although we observed these problems in specific implementations of HTTP and TCP (Apache-1.1b4 and SunOS 4.1.3, respectively), we believe that these problems occur more widely. Solutions for efficient batching of HTTP headers + data without delays involve TCP_NODELAY, and MSG_MORE / SPLICE_F_MORE / TCP_CORK / TCP_NOPUSH. Possibly TCP_QUICKACK may come in handy. Same for any protocol really, but HTTP is the one where there tends to be a separate sendmsg() and sendfile() on Linux.