I wonder why the file handle approach (fh) is slower here, when it was faster in this test:

Re: Is foreach split Optimized?

Benchmark from post linked above:

Test Code

    filehandle => sub {
        my @lines;
        open my $str_fh, "<", \$str or die "cannot open fh $!";
        while (<$str_fh>) {
            chomp;
            s/o/i/g;
            push @lines, $_;            
        }
    },
[download]

Results (Perl 5.26, {Windows,Linux,MacOS,???}?)

perlbrew exec bench_script.pl

# Other versions of Perl, omitted for brevity - see original link
#   for the "gories..."
...

perl-5.26.0
==========
             Rate      index      regex      split filehandle
index      3.00/s         --       -25%       -49%       -53%
regex      3.98/s        33%         --       -33%       -37%
split      5.91/s        97%        49%         --        -6%
filehandle 6.31/s       111%        59%         7%         --
[download]

Test using Perl 5.30 / 10 secs per test

Here is what I get using Perl 5.30 with 10 seconds per iteration in order to facilitate more accuracy (Linux Kubuntu-VM 5.1.10-050110-generic #201906151034 SMP Sat Jun 15 10:36:59 UTC 2019 x86_64 GNU/Linux):

Note #1: Keep in mind that this was run on a Linux VM on a Windows 10 host

Note #2: As you can see from the rates, it is a really Really REALLY fast host, where "really fast" implies "World Record Holder" of sorts fast

perl-5.30.0
===========
             Rate      regex      index      split filehandle
regex      9.98/s         --       -11%       -32%       -33%
index      11.2/s        12%         --       -23%       -25%
split      14.6/s        46%        30%         --        -2%
filehandle 14.9/s        49%        33%         2%         --
[download]

Note #3: Decided to run it on the Windows 10 host itself, but unfortunately I only have Perl 5.28.1 installed, so it's not an apple to apple comparison with above:

perl-5.28.1 (Windows 10 Pro)
============================
             Rate      regex      index filehandle      split
regex      8.09/s         --       -14%       -17%       -33%
index      9.46/s        17%         --        -3%       -22%
filehandle 9.73/s        20%         3%         --       -20%
split      12.2/s        50%        29%        25%         --
[download]

Note #4: Surprisingly, the Linux version in a VM ran faster than the native Windows version. I attribute this to either a difference between the Perl versions or a bad build on the Windows side

Note #5: Found the culprit on why it's slower on the Windows side (gcc was used instead of Visual C++):

perl -V
=======

==> cc='gcc'
    ccflags =' -s -O2 -DWIN32 -DWIN64 -DCONSERVATIVE -D__USE_MINGW_ANS
+I_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLIC
+IT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bitfields'     
+                                                               
    optimize='-s -O2'
    cppflags='-DWIN32'
    ccversion=''
    gccversion='7.1.0'
...
  Built under MSWin32
  Compiled at Dec  2 2018 14:30:03
  @INC:
    C:/Strawberry/perl/site/lib
    C:/Strawberry/perl/vendor/lib
    C:/Strawberry/perl/lib
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