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)Â