From: Tobias Klauser <tklauser@distanz.ch>
Date: Wed, 24 Jan 2024 21:14:49 +0000 (+0100)
Subject: net/netip: optimize Addr.MarshalText allocation for 4in6 addresses
X-Git-Tag: go1.23rc1~1388
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=700edbf73e16e2c55d59a917233662bad88623bc;p=gostls13.git

net/netip: optimize Addr.MarshalText allocation for 4in6 addresses

name                           old time/op    new time/op    delta
AddrMarshalText/v4-8             18.5ns ± 1%    18.8ns ± 1%   +1.40%  (p=0.000 n=9+10)
AddrMarshalText/v6-8             58.0ns ± 0%    57.5ns ± 0%   -0.93%  (p=0.000 n=9+10)
AddrMarshalText/v6_ellipsis-8    61.4ns ± 0%    60.4ns ± 0%   -1.65%  (p=0.000 n=10+9)
AddrMarshalText/v6_v4-8          25.7ns ± 0%    26.2ns ± 1%   +1.86%  (p=0.000 n=10+10)
AddrMarshalText/v6_zone-8        61.8ns ± 0%    60.8ns ± 0%   -1.63%  (p=0.000 n=10+9)

name                           old alloc/op   new alloc/op   delta
AddrMarshalText/v4-8              16.0B ± 0%     16.0B ± 0%     ~     (all equal)
AddrMarshalText/v6-8              48.0B ± 0%     48.0B ± 0%     ~     (all equal)
AddrMarshalText/v6_ellipsis-8     48.0B ± 0%     48.0B ± 0%     ~     (all equal)
AddrMarshalText/v6_v4-8           48.0B ± 0%     32.0B ± 0%  -33.33%  (p=0.000 n=10+10)
AddrMarshalText/v6_zone-8         48.0B ± 0%     48.0B ± 0%     ~     (all equal)

name                           old allocs/op  new allocs/op  delta
AddrMarshalText/v4-8               1.00 ± 0%      1.00 ± 0%     ~     (all equal)
AddrMarshalText/v6-8               1.00 ± 0%      1.00 ± 0%     ~     (all equal)
AddrMarshalText/v6_ellipsis-8      1.00 ± 0%      1.00 ± 0%     ~     (all equal)
AddrMarshalText/v6_v4-8            1.00 ± 0%      1.00 ± 0%     ~     (all equal)
AddrMarshalText/v6_zone-8          1.00 ± 0%      1.00 ± 0%     ~     (all equal)

Change-Id: Ib298a0fb9ec6b55e37d0559dad387242dc82aab9
Reviewed-on: https://go-review.googlesource.com/c/go/+/557776
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
---

diff --git a/src/net/netip/netip.go b/src/net/netip/netip.go
index 156f01e11e..e566a4861f 100644
--- a/src/net/netip/netip.go
+++ b/src/net/netip/netip.go
@@ -949,14 +949,15 @@ func (ip Addr) MarshalText() ([]byte, error) {
 		b := make([]byte, 0, max)
 		return ip.appendTo4(b), nil
 	default:
-		max := len("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff%enp5s0")
-		b := make([]byte, 0, max)
 		if ip.Is4In6() {
+			max := len("::ffff:255.255.255.255%enp5s0")
+			b := make([]byte, 0, max)
 			return ip.appendTo4In6(b), nil
 		}
+		max := len("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff%enp5s0")
+		b := make([]byte, 0, max)
 		return ip.appendTo6(b), nil
 	}
-
 }
 
 // UnmarshalText implements the encoding.TextUnmarshaler interface.
diff --git a/src/net/netip/netip_test.go b/src/net/netip/netip_test.go
index a748ac34f1..d80582139e 100644
--- a/src/net/netip/netip_test.go
+++ b/src/net/netip/netip_test.go
@@ -1715,11 +1715,15 @@ func BenchmarkIPStringExpanded(b *testing.B) {
 	}
 }
 
-func BenchmarkIPMarshalText(b *testing.B) {
-	b.ReportAllocs()
-	ip := MustParseAddr("66.55.44.33")
-	for i := 0; i < b.N; i++ {
-		sinkBytes, _ = ip.MarshalText()
+func BenchmarkAddrMarshalText(b *testing.B) {
+	for _, test := range parseBenchInputs {
+		ip := MustParseAddr(test.ip)
+		b.Run(test.name, func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				sinkBytes, _ = ip.MarshalText()
+			}
+		})
 	}
 }