splice vs userspace copy on containerd/fifo using Go

gistfile1.txt

goos: linux
goarch: amd64
pkg: github.com/containerd/fifo
BenchmarkRawCopy/8B-4 	          300000	      4869 ns/op	   1.44 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/16B-4         	  300000	      4688 ns/op	   3.20 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/32B-4         	  300000	      4312 ns/op	   7.19 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/64B-4         	  300000	      4447 ns/op	  14.16 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/1024B-4       	  300000	      4415 ns/op	 231.66 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/4096B-4       	  300000	      4410 ns/op	 928.50 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/8192B-4       	  300000	      5215 ns/op	1570.37 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/16384B-4      	  300000	      4576 ns/op	3579.48 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/32768B-4      	  300000	      4456 ns/op	7353.41 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/65536B-4      	  200000	      8266 ns/op	7927.84 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/131072B-4     	  200000	      9898 ns/op	13241.46 MB/s	     176 B/op	       8 allocs/op
BenchmarkRawCopy/262144B-4     	  200000	     10128 ns/op	25882.03 MB/s	     176 B/op	       8 allocs/op
BenchmarkUserCopy/8B-4         	  200000	      5444 ns/op	   1.29 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/16B-4        	  300000	      5185 ns/op	   2.89 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/32B-4        	  300000	      5449 ns/op	   5.69 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/64B-4        	  300000	      5323 ns/op	  11.83 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/1024B-4      	  300000	      5274 ns/op	 193.96 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/4096B-4      	  300000	      5659 ns/op	 723.60 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/8192B-4      	  200000	      7497 ns/op	1092.45 MB/s	     314 B/op	       1 allocs/op
BenchmarkUserCopy/16384B-4     	  200000	      8937 ns/op	1833.03 MB/s	     315 B/op	       1 allocs/op
BenchmarkUserCopy/32768B-4     	  200000	     11316 ns/op	2895.61 MB/s	     317 B/op	       1 allocs/op
BenchmarkUserCopy/65536B-4     	   30000	     39180 ns/op	1672.64 MB/s	     613 B/op	       1 allocs/op
BenchmarkUserCopy/131072B-4    	   20000	     57826 ns/op	2266.63 MB/s	     623 B/op	       1 allocs/op
BenchmarkUserCopy/262144B-4    	   10000	    110779 ns/op	2366.36 MB/s	     660 B/op	       1 allocs/op