• Carlos Eduardo Seo's avatar
    runtime: fix regression in BenchmarkCompareBytes* for ppc64x · 4641d78a
    Carlos Eduardo Seo authored
    Between go1.7 and go1.8, a performance regression was introduced in some of the
    BenchmarkCompareBytes benchmarks.
    
    Go1.7 vs Go1.8:
    BenchmarkCompareBytesToNil-8               7.44          8.44          +13.44%
    BenchmarkCompareBytesIdentical-8           6.96          11.5          +65.23%
    BenchmarkCompareBytesBigIdentical-8        6.65          47112         +708351.13%
    
    This change fixes the problem by optimizing the case where the byte slices being
    compared are equal:
    
    Go1.9 vs current:
    BenchmarkCompareBytesToNil-8               7.35          7.00          -4.76%
    BenchmarkCompareBytesIdentical-8           11.4          6.81          -40.26%
    BenchmarkCompareBytesBigIdentical-8        48396         9.26          -99.98%
    
    runtime.cmpstring can benefit from the same approach and is also changed.
    
    Change-Id: I3cb25f59d8b940a83a2cf687eea764cfeff90688
    Reviewed-on: https://go-review.googlesource.com/59650
    Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    Reviewed-by: 's avatarLynn Boger <laboger@linux.vnet.ibm.com>
    4641d78a
asm_ppc64x.s 35.6 KB