Add an osImpl interface that can be stateful and thus more efficient
between calls. It will later be implemented by all OSes but for now
this change only adds a Linux implementation.
Remove Port.inode. It was only used by Linux and moves into its osImpl.
Don't reopen /proc/net/* files on each run. Turns out you can just
keep then open and seek to the beginning and reread and the contents
are fresh.
name old time/op new time/op delta
GetListIncremental-8 7.29ms ± 2% 6.53ms ± 1% -10.50% (p=0.000 n=9+9)
name old alloc/op new alloc/op delta
GetListIncremental-8 1.30kB ±13% 0.70kB ± 5% -46.38% (p=0.000 n=9+10)
name old allocs/op new allocs/op delta
GetListIncremental-8 33.2 ±11% 18.0 ± 0% -45.82% (p=0.000 n=9+10)
Updates #5958
Change-Id: I4be83463cbd23c2e2fa5d0bdf38560004f53401b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
036f70b7b4