runtime: make span map sparse
This splits the span map into separate chunks for every 64MB of the
heap. The span map chunks now live in the same indirect structure as
the bitmap.
Updates #10460.
This causes a slight improvement in compilebench and the x/benchmarks
garbage benchmark. I'm not sure why it improves performance.
name old time/op new time/op delta
Template 185ms ± 1% 184ms ± 1% ~ (p=0.315 n=9+10)
Unicode 86.9ms ± 1% 86.9ms ± 3% ~ (p=0.356 n=9+10)
GoTypes 602ms ± 1% 599ms ± 0% -0.59% (p=0.002 n=9+10)
Compiler 2.89s ± 0% 2.87s ± 1% -0.50% (p=0.003 n=9+9)
SSA 7.25s ± 0% 7.29s ± 1% ~ (p=0.400 n=9+10)
Flate 118ms ± 1% 118ms ± 2% ~ (p=0.065 n=10+9)
GoParser 147ms ± 2% 147ms ± 1% ~ (p=0.549 n=10+9)
Reflect 403ms ± 1% 401ms ± 1% -0.47% (p=0.035 n=9+10)
Tar 176ms ± 1% 175ms ± 1% -0.59% (p=0.013 n=10+9)
XML 211ms ± 1% 209ms ± 1% -0.83% (p=0.011 n=10+10)
(https://perf.golang.org/search?q=upload:
20171231.1)
name old time/op new time/op delta
Garbage/benchmem-MB=64-12 2.24ms ± 1% 2.23ms ± 1% -0.36% (p=0.001 n=20+19)
(https://perf.golang.org/search?q=upload:
20171231.2)
Change-Id: I2563f8704ab9812434947faf293c5327f9b0d07a
Reviewed-on: https://go-review.googlesource.com/85885
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>