perl-5.38.2
==========
              Rate split_grep  (?{}) substr   chop chomp  =()= while index rindex split_by tr / y
split_grep   214/s         --    -4%   -23%   -36%  -47%  -68%  -70%  -77%   -79%     -99%   -99%
(?{})        222/s         4%     --   -20%   -34%  -45%  -67%  -69%  -77%   -78%     -98%   -99%
substr       279/s        30%    26%     --   -17%  -31%  -59%  -61%  -71%   -73%     -98%   -99%
chop         336/s        57%    51%    20%     --  -16%  -50%  -53%  -65%   -67%     -98%   -99%
chomp        403/s        88%    81%    44%    20%    --  -40%  -44%  -58%   -61%     -97%   -99%
=()=         673/s       214%   203%   141%   100%   67%    --   -6%  -29%   -34%     -95%   -98%
while        718/s       235%   223%   157%   114%   78%    7%    --  -24%   -30%     -95%   -98%
index        948/s       342%   326%   240%   182%  135%   41%   32%    --    -8%     -93%   -97%
rindex      1028/s       380%   362%   268%   206%  155%   53%   43%    8%     --     -93%   -97%
split_by   14354/s      6599%  6359%  5045%  4170% 3466% 2032% 1899% 1415%  1297%       --   -59%
tr / y     34600/s     16047% 15470% 12301% 10192% 8496% 5039% 4718% 3551%  3267%     141%     --

perl-5.32.0
==========
              Rate split_grep  (?{}) substr  chomp  chop  =()= while rindex index split_by tr / y
split_grep   163/s         --   -16%   -45%   -46%  -53%  -68%  -78%   -83%  -83%     -99%  -100%
(?{})        194/s        19%     --   -34%   -36%  -44%  -62%  -73%   -79%  -79%     -99%   -99%
substr       296/s        82%    52%     --    -2%  -14%  -42%  -59%   -68%  -68%     -98%   -99%
chomp        302/s        85%    55%     2%     --  -13%  -41%  -59%   -68%  -68%     -98%   -99%
chop         345/s       112%    78%    17%    14%    --  -32%  -53%   -63%  -63%     -98%   -99%
=()=         511/s       213%   163%    72%    69%   48%    --  -30%   -46%  -46%     -97%   -99%
while        731/s       348%   276%   147%   142%  112%   43%    --   -22%  -22%     -96%   -98%
rindex       939/s       476%   383%   217%   211%  172%   84%   28%     --   -0%     -95%   -97%
index        939/s       476%   383%   217%   211%  172%   84%   28%     0%    --     -95%   -97%
split_by   18553/s     11271%  9442%  6162%  6048% 5272% 3532% 2436%  1876% 1875%       --   -46%
tr / y     34462/s     21022% 17623% 11531% 11319% 9878% 6645% 4611%  3570% 3568%      86%     --

perl-5.20.1
==========
              Rate split_grep substr   chop   =()=  chomp (?{}) while index rindex split_by tr / y
split_grep   181/s         --   -25%   -38%   -41%   -41%  -54%  -73%  -74%   -74%     -99%   -99%
substr       241/s        33%     --   -17%   -21%   -21%  -38%  -64%  -65%   -66%     -99%   -99%
chop         290/s        61%    20%     --    -5%    -5%  -26%  -57%  -58%   -59%     -98%   -99%
=()=         304/s        68%    26%     5%     --    -1%  -22%  -55%  -56%   -57%     -98%   -99%
chomp        307/s        70%    27%     6%     1%     --  -22%  -54%  -56%   -56%     -98%   -99%
(?{})        392/s       117%    62%    35%    29%    28%    --  -42%  -44%   -44%     -98%   -99%
while        673/s       273%   179%   132%   121%   120%   72%    --   -3%    -4%     -96%   -98%
index        697/s       286%   189%   140%   129%   127%   78%    4%    --    -1%     -96%   -98%
rindex       704/s       289%   192%   142%   131%   129%   80%    5%    1%     --     -96%   -98%
split_by   16747/s      9166%  6845%  5665%  5403%  5360% 4177% 2387% 2302%  2280%       --   -51%
tr / y     34296/s     18876% 14124% 11707% 11170% 11081% 8658% 4994% 4819%  4773%     105%     --