Repository: go
Issue: net/http: benchmarks fail on sierra with 'too many open files'
Labels: Testing,help wanted,NeedsFix

Sample run excerpt:

```bash
BenchmarkCookieString-8                      	 2000000	       900 ns/op	     384 B/op	       3 allocs/op
BenchmarkReadSetCookies-8                    	  500000	      3703 ns/op	     960 B/op	      17 allocs/op
BenchmarkReadCookies-8                       	  300000	      4948 ns/op	    2008 B/op	      16 allocs/op
BenchmarkHeaderWriteSubset-8                 	 3000000	       545 ns/op	       0 B/op	       0 allocs/op
BenchmarkReadRequestChrome-8                 	  500000	      3187 ns/op	 191.68 MB/s	    1809 B/op	      14 allocs/op
BenchmarkReadRequestCurl-8                   	 1000000	      1663 ns/op	  46.90 MB/s	     880 B/op	       9 allocs/op
BenchmarkReadRequestApachebench-8            	 1000000	      1670 ns/op	  49.10 MB/s	     883 B/op	       9 allocs/op
BenchmarkReadRequestSiege-8                  	 1000000	      2161 ns/op	  69.87 MB/s	     965 B/op	      11 allocs/op
BenchmarkReadRequestWrk-8                    	 1000000	      1682 ns/op	  23.78 MB/s	     832 B/op	       7 allocs/op
BenchmarkClientServer-8                      	   20000	     71011 ns/op	    4962 B/op	      67 allocs/op
BenchmarkClientServerParallel4-8             	  100000	     15276 ns/op	    4937 B/op	      64 allocs/op
BenchmarkClientServerParallel64-8            	2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 5ms
2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 5ms
2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 10ms
2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 20ms
2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 40ms
2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 80ms
2017/01/22 11:19:46 http: Accept error: accept tcp 127.0.0.1:60387: accept: too many open files; retrying in 5ms
   10000	    135870 ns/op	    4749 B/op	      63 allocs/op
--- BENCH: BenchmarkClientServerParallel64-8
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	serve_test.go:4494: Get: Get http://127.0.0.1:60387: dial tcp 127.0.0.1:60387: socket: too many open files
	... [output truncated]
BenchmarkClientServerParallelTLS4-8          	  100000	     15757 ns/op	    4945 B/op	      64 allocs/op
BenchmarkClientServerParallelTLS64-8         	2017/01/22 11:19:49 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:49 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:49 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 10ms
2017/01/22 11:19:49 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 20ms
2017/01/22 11:19:49 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 40ms
2017/01/22 11:19:49 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:50 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:50 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:50 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:50 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:50 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
2017/01/22 11:19:50 http: Accept error: accept tcp 127.0.0.1:60976: accept: too many open files; retrying in 5ms
    5000	    475368 ns/op	    6175 B/op	      80 allocs/op
--- BENCH: BenchmarkClientServerParallelTLS64-8
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	serve_test.go:4494: Get: Get https://127.0.0.1:60976: dial tcp 127.0.0.1:60976: socket: too many open files
	... [output truncated]
BenchmarkServer-8                            	   20000	     75523 ns/op	    2341 B/op	      21 allocs/op
BenchmarkClient-8                            	   20000	     72795 ns/op	    3351 B/op	      50 allocs/op
```