archive/zip: make benchmarks more representative
Currently zip benchmarks spend 60% in the rleBuffer code,
which is used only to test zip archive/zip itself:
17.48s 37.02% 37.02% 18.12s 38.37% archive/zip.(*rleBuffer).ReadAt
9.51s 20.14% 57.16% 10.43s 22.09% archive/zip.(*rleBuffer).Write
9.15s 19.38% 76.54% 10.85s 22.98% compress/flate.(*compressor).deflate
This means that benchmarks currently test performance of test helper.
Updating ReadAt/Write methods to be more performant makes benchmarks closer to real world.
name old time/op new time/op delta
CompressedZipGarbage-8 2.34ms ± 0% 2.34ms ± 1% ~ (p=0.684 n=10+10)
Zip64Test-8 58.1ms ± 2% 10.7ms ± 1% -81.54% (p=0.000 n=10+10)
Zip64TestSizes/4096-8 4.05µs ± 2% 3.65µs ± 5% -9.96% (p=0.000 n=9+10)
Zip64TestSizes/
1048576-8 238µs ± 0% 43µs ± 0% -82.06% (p=0.000 n=10+10)
Zip64TestSizes/
67108864-8 15.3ms ± 1% 2.6ms ± 0% -83.12% (p=0.000 n=10+9)
name old alloc/op new alloc/op delta
CompressedZipGarbage-8 17.9kB ±14% 16.0kB ±24% -10.48% (p=0.026 n=9+10)
name old allocs/op new allocs/op delta
CompressedZipGarbage-8 44.0 ± 0% 44.0 ± 0% ~ (all equal)
Change-Id: Idfd920d0e4bed4aec2f5be84dc7e3919d9f1dd2d
Reviewed-on: https://go-review.googlesource.com/83857
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>