net, runtime: enable runtime-integrated pollster on Linux/ARM.
Results from linux/arm on a Samsung Chromebook (from dfc):
localhost(~/go/src/pkg/net) % ~/go/misc/benchcmp {old,new}.txt
benchmark old ns/op new ns/op delta
BenchmarkTCP4OneShot 568840 350526 -38.38%
BenchmarkTCP4OneShot-2 359054 206708 -42.43%
BenchmarkTCP4OneShotTimeout 637464 363550 -42.97%
BenchmarkTCP4OneShotTimeout-2 374255 216695 -42.10%
BenchmarkTCP4Persistent 184974 64984 -64.87%
BenchmarkTCP4Persistent-2 109902 47195 -57.06%
BenchmarkTCP4PersistentTimeout 210039 64789 -69.15%
BenchmarkTCP4PersistentTimeout-2 124284 43374 -65.10%
BenchmarkTCP6OneShot 672278 362116 -46.14%
BenchmarkTCP6OneShot-2 383631 216400 -43.59%
BenchmarkTCP6OneShotTimeout 680740 378306 -44.43%
BenchmarkTCP6OneShotTimeout-2 397524 230152 -42.10%
BenchmarkTCP6Persistent 172346 65292 -62.12%
BenchmarkTCP6Persistent-2 106229 42096 -60.37%
BenchmarkTCP6PersistentTimeout 161149 65138 -59.58%
BenchmarkTCP6PersistentTimeout-2 152276 44548 -70.75%
R=golang-dev, dave, bradfitz, dvyukov, rsc
CC=golang-dev
https://golang.org/cl/
7820045