89ccfe4962
The Reader implementation is slow because it operates on a rune-by-rune basis via bufio.Reader.ReadRune. We speed this up by operating on entire lines that we read from bufio.Reader.ReadSlice. In order to ensure that we read the full line, we augment ReadSlice in our Reader.readLine method to automatically expand the slice if bufio.ErrBufferFull is every hit. This change happens to fix #19410 because it no longer relies on rune-by-rune parsing and only searches for the relevant delimiter rune. In order to keep column accounting simple and consistent, this change reverts parts of CL 52830. This CL is an alternative to CL 36270 and builds on some of the ideas from that change by Diogo Pinela. name old time/op new time/op delta Read-8 3.12µs ± 1% 2.54µs ± 2% -18.76% (p=0.000 n=10+9) ReadWithFieldsPerRecord-8 3.12µs ± 1% 2.53µs ± 1% -18.91% (p=0.000 n=9+9) ReadWithoutFieldsPerRecord-8 3.13µs ± 0% 2.57µs ± 3% -18.07% (p=0.000 n=10+10) ReadLargeFields-8 52.3µs ± 1% 5.3µs ± 2% -89.93% (p=0.000 n=10+9) ReadReuseRecord-8 2.05µs ± 1% 1.40µs ± 1% -31.48% (p=0.000 n=10+9) ReadReuseRecordWithFieldsPerRecord-8 2.05µs ± 1% 1.41µs ± 0% -31.03% (p=0.000 n=10+9) ReadReuseRecordWithoutFieldsPerRecord-8 2.06µs ± 1% 1.40µs ± 1% -31.70% (p=0.000 n=9+10) ReadReuseRecordLargeFields-8 50.9µs ± 0% 4.1µs ± 3% -92.01% (p=0.000 n=10+10) name old alloc/op new alloc/op Read-8 664B ± 0% 664B ± 0% ReadWithFieldsPerRecord-8 664B ± 0% 664B ± 0% ReadWithoutFieldsPerRecord-8 664B ± 0% 664B ± 0% ReadLargeFields-8 3.94kB ± 0% 3.94kB ± 0% ReadReuseRecord-8 24.0B ± 0% 24.0B ± 0% ReadReuseRecordWithFieldsPerRecord-8 24.0B ± 0% 24.0B ± 0% ReadReuseRecordWithoutFieldsPerRecord-8 24.0B ± 0% 24.0B ± 0% ReadReuseRecordLargeFields-8 2.98kB ± 0% 2.98kB ± 0% name old allocs/op new allocs/op Read-8 18.0 ± 0% 18.0 ± 0% ReadWithFieldsPerRecord-8 18.0 ± 0% 18.0 ± 0% ReadWithoutFieldsPerRecord-8 18.0 ± 0% 18.0 ± 0% ReadLargeFields-8 24.0 ± 0% 24.0 ± 0% ReadReuseRecord-8 8.00 ± 0% 8.00 ± 0% ReadReuseRecordWithFieldsPerRecord-8 8.00 ± 0% 8.00 ± 0% ReadReuseRecordWithoutFieldsPerRecord-8 8.00 ± 0% 8.00 ± 0% ReadReuseRecordLargeFields-8 12.0 ± 0% 12.0 ± 0% Updates #22352 Updates #19019 Fixes #16791 Fixes #19410 Change-Id: I31c27cfcc56880e6abac262f36c947179b550bbf Reviewed-on: https://go-review.googlesource.com/72150 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> |
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