Here's the current performance numbers for the go1 benchmarks, comparing tip relative to go1.6:
name old time/op new time/op delta
BinaryTree17-12 3.16s ±14% 2.77s ± 3% -12.33% (p=0.000 n=10+9)
Fannkuch11-12 2.68s ± 1% 2.21s ± 1% -17.72% (p=0.000 n=10+9)
FmtFprintfEmpty-12 52.5ns ± 3% 50.2ns ± 2% -4.42% (p=0.000 n=10+10)
FmtFprintfString-12 175ns ± 1% 163ns ± 0% -6.55% (p=0.000 n=9+9)
FmtFprintfInt-12 170ns ± 6% 160ns ± 0% -5.77% (p=0.000 n=10+8)
FmtFprintfIntInt-12 272ns ± 0% 260ns ± 1% -4.62% (p=0.000 n=8+9)
FmtFprintfPrefixedInt-12 245ns ± 1% 228ns ± 0% -7.11% (p=0.000 n=9+8)
FmtFprintfFloat-12 328ns ± 1% 303ns ± 1% -7.48% (p=0.000 n=9+8)
FmtManyArgs-12 1.06µs ± 2% 0.96µs ± 0% -9.61% (p=0.000 n=10+9)
GobDecode-12 8.20ms ± 3% 7.75ms ± 2% -5.44% (p=0.000 n=8+9)
GobEncode-12 6.99ms ± 1% 6.42ms ± 2% -8.14% (p=0.000 n=10+9)
Gzip-12 336ms ± 1% 289ms ± 1% -13.97% (p=0.000 n=9+9)
Gunzip-12 44.2ms ± 1% 40.7ms ± 1% -7.84% (p=0.000 n=9+10)
HTTPClientServer-12 223µs ± 7% 208µs ± 6% -6.56% (p=0.000 n=10+10)
JSONEncode-12 17.7ms ± 1% 16.7ms ± 1% -5.58% (p=0.000 n=8+9)
JSONDecode-12 58.6ms ± 0% 54.3ms ± 1% -7.24% (p=0.000 n=9+8)
Mandelbrot200-12 4.18ms ± 3% 4.40ms ± 1% +5.24% (p=0.000 n=10+9)
GoParse-12 3.74ms ± 2% 3.56ms ± 2% -4.84% (p=0.000 n=9+10)
RegexpMatchEasy0_32-12 102ns ± 1% 79ns ± 0% -22.93% (p=0.000 n=10+10)
RegexpMatchEasy0_1K-12 352ns ± 1% 251ns ± 0% -28.60% (p=0.000 n=8+10)
RegexpMatchEasy1_32-12 87.5ns ± 0% 76.5ns ± 1% -12.60% (p=0.000 n=8+10)
RegexpMatchEasy1_1K-12 515ns ± 1% 410ns ± 3% -20.37% (p=0.000 n=10+10)
RegexpMatchMedium_32-12 138ns ± 1% 122ns ± 1% -11.50% (p=0.000 n=10+10)
RegexpMatchMedium_1K-12 40.4µs ± 1% 37.0µs ± 0% -8.43% (p=0.000 n=10+10)
RegexpMatchHard_32-12 2.19µs ± 1% 1.94µs ± 4% -11.42% (p=0.000 n=8+10)
RegexpMatchHard_1K-12 66.2µs ± 1% 58.7µs ± 2% -11.32% (p=0.000 n=9+10)
Revcomp-12 594ms ± 1% 416ms ± 8% -29.96% (p=0.000 n=8+10)
Template-12 70.5ms ± 1% 65.0ms ± 1% -7.87% (p=0.000 n=8+10)
TimeParse-12 358ns ± 1% 341ns ± 0% -4.55% (p=0.000 n=10+9)
TimeFormat-12 363ns ± 1% 369ns ± 7% ~ (p=0.186 n=9+10)
Attached are the same numbers in graphical form.
Tip compiler (with SSA internal checks off) is about 7% slower than go1.6 to compile net/http (go test -a -c -gcflags=-d=ssa/check/off net/http)