[Bug libc/24872] __memmove_avx_unaligned_erms() performs significantly much slower than __memcpy_ssse3()

[skpgkp2 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=24872

--- Comment #3 from Sunil Pandey <skpgkp2 at gmail dot com> ---
Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz, for glibc master branch,
benchtests/bench-memcpy-large. avx_unaligned_erms is faster than ssse3

shows:

Function: memcpy
Variant: large
                                    __memcpy_avx_unaligned_erms __memcpy_ssse3
========================================================================================================================
    length=65543, align1=0, align2=0:      4633.50           6862.62 (-48.11%)  
    length=65551, align1=0, align2=3:      5152.25           6498.88 (-26.14%)  
    length=65567, align1=3, align2=0:      5052.12           6385.75 (-26.40%)  
    length=65599, align1=3, align2=5:      5811.12           6420.50 (-10.49%)  
   length=131079, align1=0, align2=0:      9181.50          12541.40 (-36.59%)  
   length=131087, align1=0, align2=3:     10162.00          12765.60 (-25.62%)  
   length=131103, align1=3, align2=0:      9961.50          12600.60 (-26.49%)  
   length=131135, align1=3, align2=5:     10134.60          12671.10 (-25.03%)  
   length=262151, align1=0, align2=0:     17199.90          24132.40 (-40.31%)  
   length=262159, align1=0, align2=3:     19601.20          24818.40 (-26.62%)  
   length=262175, align1=3, align2=0:     18511.60          23472.00 (-26.80%)  
   length=262207, align1=3, align2=5:     18139.80          22806.60 (-25.73%)  
   length=524295, align1=0, align2=0:     43515.40          67501.40 (-55.12%)  
   length=524303, align1=0, align2=3:     44062.60          70280.60 (-59.50%)  
   length=524319, align1=3, align2=0:     41980.60          67370.60 (-60.48%)  
   length=524351, align1=3, align2=5:     39343.60          65058.90 (-65.36%)  
  length=1048583, align1=0, align2=0:    637645.00         704786.00 (-10.53%)  
  length=1048591, align1=0, align2=3:    546501.00         551314.00 ( -0.88%)  
  length=1048607, align1=3, align2=0:    493258.00         542408.00 ( -9.96%)  
  length=1048639, align1=3, align2=5:    457022.00         513160.00 (-12.28%)  
  length=2097159, align1=0, align2=0:    928221.00        1055570.00 (-13.72%)  
  length=2097167, align1=0, align2=3:    934195.00         975572.00 ( -4.43%)  
  length=2097183, align1=3, align2=0:    929252.00        1052450.00 (-13.26%)  
  length=2097215, align1=3, align2=5:    934500.00        1047300.00 (-12.07%)  
  length=4194311, align1=0, align2=0:   1901330.00        2124790.00 (-11.75%)  
  length=4194319, align1=0, align2=3:   1931670.00        1954720.00 ( -1.19%)  
  length=4194335, align1=3, align2=0:   1906640.00        2113830.00 (-10.87%)  
  length=4194367, align1=3, align2=5:   1927260.00        2108930.00 ( -9.43%)  
  length=8388615, align1=0, align2=0:   3802180.00        4254990.00 (-11.91%)  
  length=8388623, align1=0, align2=3:   3858480.00        3962610.00 ( -2.70%)  
  length=8388639, align1=3, align2=0:   3797900.00        4233080.00 (-11.46%)  
  length=8388671, align1=3, align2=5:   3848300.00        4252190.00 (-10.50%)  
 length=16777223, align1=0, align2=0:   7604180.00        8557160.00 (-12.53%)  
 length=16777231, align1=0, align2=3:   7705930.00        7923390.00 ( -2.82%)  
 length=16777247, align1=3, align2=0:   7612860.00        8487690.00 (-11.49%)  
 length=16777279, align1=3, align2=5:   7708250.00        8512540.00 (-10.43%)  
 length=33554439, align1=0, align2=0:  15591300.00       17522200.00 (-12.38%)  
 length=33554447, align1=0, align2=3:  15808700.00       16259700.00 ( -2.85%)  
 length=33554463, align1=3, align2=0:  15535400.00       17188100.00 (-10.64%)  
 length=33554495, align1=3, align2=5:  15714100.00       17517900.00 (-11.48%)

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