Float type from a mutex to atomic bit array in a manner akin to
Google Guava's AtomicDouble[0], including adding a benchmark for the
type (benchcmp included below) along with some expvar_test.go cruft
being fixed.
benchmark old ns/op new ns/op delta
BenchmarkFloatSet 115 9.37 -91.85%
BenchmarkFloatAdd 114 17.1 -85.00%
benchmark old allocs new allocs delta
BenchmarkFloatSet 0 0 +0.00%
BenchmarkFloatAdd 0 0 +0.00%
benchmark old bytes new bytes delta
BenchmarkFloatSet 0 0 +0.00%
BenchmarkFloatAdd 0 0 +0.00%
[0] - http://goo.gl/m4dtlI
Change-Id: I4ce6a913734ec692e3ed243f6e6f7c11da4c6036
Reviewed-on: https://go-review.googlesource.com/3687 Reviewed-by: Rob Pike <r@golang.org>