net/http: simplify transfer body; reduces allocations too

benchmark                                   old ns/op    new ns/op    delta
BenchmarkServerFakeConnNoKeepAlive              14431        14247   -1.28%
BenchmarkServerFakeConnWithKeepAlive            11618        11357   -2.25%
BenchmarkServerFakeConnWithKeepAliveLite         6735         6427   -4.57%
BenchmarkServerHandlerTypeLen                    8842         8740   -1.15%
BenchmarkServerHandlerNoLen                      8001         7828   -2.16%
BenchmarkServerHandlerNoType                     8270         8227   -0.52%
BenchmarkServerHandlerNoHeader                   6148         5920   -3.71%

benchmark                                  old allocs   new allocs    delta
BenchmarkServerFakeConnNoKeepAlive                 30           29   -3.33%
BenchmarkServerFakeConnWithKeepAlive               25           24   -4.00%
BenchmarkServerFakeConnWithKeepAliveLite           10            9  -10.00%
BenchmarkServerHandlerTypeLen                      18           17   -5.56%
BenchmarkServerHandlerNoLen                        15           14   -6.67%
BenchmarkServerHandlerNoType                       16           15   -6.25%
BenchmarkServerHandlerNoHeader                     10            9  -10.00%

benchmark                                   old bytes    new bytes    delta
BenchmarkServerFakeConnNoKeepAlive               2557         2492   -2.54%
BenchmarkServerFakeConnWithKeepAlive             2260         2194   -2.92%
BenchmarkServerFakeConnWithKeepAliveLite         1092         1026   -6.04%
BenchmarkServerHandlerTypeLen                    1941         1875   -3.40%
BenchmarkServerHandlerNoLen                      1898         1832   -3.48%
BenchmarkServerHandlerNoType                     1906         1840   -3.46%
BenchmarkServerHandlerNoHeader                   1092         1026   -6.04%

Update #5195

R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/9492044
2 files changed