runtime: increase page size to 8K
Tcmalloc uses 8K, 32K and 64K pages, and in custom setups 256K pages.
Only Chromium uses 4K pages today (in "slow but small" configuration).
The general tendency is to increase page size, because it reduces
metadata size and DTLB pressure.
This change reduces GC pause by ~10% and slightly improves other metrics.
json-1
allocated
8037492 8038689 +0.01%
allocs 105762 105573 -0.18%
cputime
158400000 155800000 -1.64%
gc-pause-one
4412234 4135702 -6.27%
gc-pause-total
2647340 2398707 -9.39%
rss
54923264 54525952 -0.72%
sys-gc
3952624 3928048 -0.62%
sys-heap
46399488 46006272 -0.85%
sys-other
5597504 5290304 -5.49%
sys-stack 393216 393216 +0.00%
sys-total
56342832 55617840 -1.29%
time
158478890 156046916 -1.53%
virtual-mem
256548864 256593920 +0.02%
garbage-1
allocated
2991113 2986259 -0.16%
allocs 62844 62652 -0.31%
cputime
16330000 15860000 -2.88%
gc-pause-one
789108229 725555211 -8.05%
gc-pause-total
3945541 3627776 -8.05%
rss
1143660544 1132253184 -1.00%
sys-gc
65609600 65806208 +0.30%
sys-heap
1032388608 1035599872 +0.31%
sys-other
37501632 22777664 -39.26%
sys-stack
8650752 8781824 +1.52%
sys-total
1144150592 1132965568 -0.98%
time
16364602 15891994 -2.89%
virtual-mem
1327296512 1313746944 -1.02%
This is the exact reincarnation of already LGTMed:
https://golang.org/cl/
45770044
which must not break darwin/freebsd after:
https://golang.org/cl/
56630043
TBR=iant
LGTM=khr, iant
R=iant, khr
CC=golang-codereviews
https://golang.org/cl/
58230043