Avoid splitting fields in the common case. Field splitting was 84% of
the overall CPU.
name old time/op new time/op delta
ParsePorts-6 33.3ms ± 2% 6.3ms ± 4% -80.97% (p=0.000 n=9+10)
name old alloc/op new alloc/op delta
ParsePorts-6 520B ±79% 408B ± 0% -21.49% (p=0.046 n=10+8)
name old allocs/op new allocs/op delta
ParsePorts-6 7.00 ± 0% 7.00 ± 0% ~ (all equal)
Updates tailscale/corp#2566
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Notably, it no longer allocates proportional to the number of open
sockets on the machine. Any alloc reduction numbers are a little
contrived with such a reduction but e.g. on a machine with 50,000
connections open:
name old time/op new time/op delta
ParsePorts-6 57.7ms ± 6% 32.8ms ± 3% -43.04% (p=0.000 n=9+10)
name old alloc/op new alloc/op delta
ParsePorts-6 24.0MB ± 0% 0.0MB ± 0% -100.00% (p=0.000 n=10+9)
name old allocs/op new allocs/op delta
ParsePorts-6 100k ± 0% 0k ± 0% -99.99% (p=0.000 n=10+10)
Updates tailscale/corp#2566
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This is important because some of those v6 sockets are actually
dual-stacked sockets, so this is our only chance of discovering
some services.
Fixes#1443.
Signed-off-by: David Anderson <danderson@tailscale.com>
Brad Fitzpatrick
David Anderson