• Josselin Costanzi's avatar
    encoding/base64: Optimize DecodeString · 31c96fc2
    Josselin Costanzi authored
    Optimize DecodeString for the common case where most of the input isn't
    a newline or a padding character.
    Also add some testcases found when fuzzing this implementation against
    upstream.
    Change Decode benchmark to run with different input sizes.
    
    name                 old time/op    new time/op    delta
    DecodeString/2-4       71.5ns ± 4%    70.0ns ± 6%     ~     (p=0.246 n=5+5)
    DecodeString/4-4        112ns ±25%      91ns ± 2%     ~     (p=0.056 n=5+5)
    DecodeString/8-4        136ns ± 5%     126ns ± 5%   -7.33%  (p=0.016 n=5+5)
    DecodeString/64-4       872ns ±29%     652ns ±21%  -25.23%  (p=0.032 n=5+5)
    DecodeString/8192-4    90.9µs ±21%    61.0µs ±13%  -32.87%  (p=0.008 n=5+5)
    
    name                 old speed      new speed      delta
    DecodeString/2-4     56.0MB/s ± 4%  57.2MB/s ± 6%     ~     (p=0.310 n=5+5)
    DecodeString/4-4     73.4MB/s ±23%  87.7MB/s ± 2%     ~     (p=0.056 n=5+5)
    DecodeString/8-4     87.8MB/s ± 5%  94.8MB/s ± 5%   +7.98%  (p=0.016 n=5+5)
    DecodeString/64-4     103MB/s ±24%   136MB/s ±19%  +32.63%  (p=0.032 n=5+5)
    DecodeString/8192-4   122MB/s ±19%   180MB/s ±11%  +47.75%  (p=0.008 n=5+5)
    
    Improves #19636
    
    Change-Id: I39667f4fb682a12b3137946d017ad999553c5780
    Reviewed-on: https://go-review.googlesource.com/34950Reviewed-by: 's avatarBrad Fitzpatrick <bradfitz@golang.org>
    Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    31c96fc2
base64.go 12.5 KB