NewContainsIPFunc was previously documented as performing poorly if
there were many netip.Prefixes to search over. As such, we never it used it
in such cases.
This updates it to use bart at a certain threshold (over 6 prefixes,
currently), at which point the bart lookup overhead pays off.
This is currently kinda useless because we're not using it. But now we
can and get wins elsewhere. And we can remove the caveat in the docs.
goos: darwin
goarch: arm64
pkg: tailscale.com/net/tsaddr
│ before │ after │
│ sec/op │ sec/op vs base │
NewContainsIPFunc/empty-8 2.215n ± 11% 2.239n ± 1% +1.08% (p=0.022 n=10)
NewContainsIPFunc/cidr-list-1-8 17.44n ± 0% 17.59n ± 6% +0.89% (p=0.000 n=10)
NewContainsIPFunc/cidr-list-2-8 27.85n ± 0% 28.13n ± 1% +1.01% (p=0.000 n=10)
NewContainsIPFunc/cidr-list-3-8 36.05n ± 0% 36.56n ± 13% +1.41% (p=0.000 n=10)
NewContainsIPFunc/cidr-list-4-8 43.73n ± 0% 44.38n ± 1% +1.50% (p=0.000 n=10)
NewContainsIPFunc/cidr-list-5-8 51.61n ± 2% 51.75n ± 0% ~ (p=0.101 n=10)
NewContainsIPFunc/cidr-list-10-8 95.65n ± 0% 68.92n ± 0% -27.94% (p=0.000 n=10)
NewContainsIPFunc/one-ip-8 4.466n ± 0% 4.469n ± 1% ~ (p=0.491 n=10)
NewContainsIPFunc/two-ip-8 8.002n ± 1% 7.997n ± 4% ~ (p=0.697 n=10)
NewContainsIPFunc/three-ip-8 27.98n ± 1% 27.75n ± 0% -0.82% (p=0.012 n=10)
geomean 19.60n 19.07n -2.71%
Updates #12486
Change-Id: I2e2320cc4384f875f41721374da536bab995c1ce
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>