There are some good benchmarking modules, but there may be easier ways:

perl -le '$text = <STDIN>; $T=time; $TestText=$text; for (1..$ARGV[0])
+ { $text =~ s/\s+,\s+|\s+,|,\s+/,/g; } print time - $T; $T=time; $Tes
+tText=$text; for (1..$ARGV[0]) { $text =~ s/\s*,\s*/,/g; } print time
+ - $T;' 1000000 </tmp/text.file
[download]

This oneliner just runs your two regexps on the same text for a specific number of loop runs. Use a number which takes at least 10, better more, seconds for each loop.
This could also be improved by using Time::HiRes.

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