Running under Python 2.7.6 on Ubuntu 14.04:

Mon Aug 29 16:17:38 2016    /tmp/profile

         90388000 function calls (88164345 primitive calls) in 2980.718 seconds

   Ordered by: internal time
   List reduced from 1293 to 10 due to restriction <10>

      ncalls       tottime  percall  cumtime  percall filename:lineno(function)
         360      2847.099    7.909 2847.099    7.909 {posix.waitpid}
     7556927        14.850    0.000   22.984    0.000 /usr/lib/python2.7/sre_parse.py:182(__next)
329052/19969        14.153    0.000   66.094    0.003 /usr/lib/python2.7/sre_parse.py:379(_parse)
21228753/21056054   11.622    0.000   11.818    0.000 {len}
    14781340         8.213    0.000    8.213    0.000 {method 'append' of 'list' objects}
501625/19869         8.185    0.000   34.260    0.002 /usr/lib/python2.7/sre_compile.py:32(_compile)
     6577687         7.884    0.000   27.879    0.000 /usr/lib/python2.7/sre_parse.py:201(get)
      486296         7.675    0.000   12.117    0.000 /usr/lib/python2.7/sre_compile.py:207(_optimize_charset)
     3228296         4.020    0.000    6.069    0.000 /usr/lib/python2.7/sre_parse.py:130(__getitem__)
     6187868         3.826    0.000    3.826    0.000 {isinstance}

--------------------------------------------------------------------------------------------------------------
Same regular-expression-intensive Python code, running under Python 2.7.12 on Ubuntu 16.04:

Mon Aug 29 16:39:39 2016    /tmp/profile

         91532568 function calls (89306823 primitive calls) in 4519.872 seconds

   Ordered by: internal time
   List reduced from 1680 to 10 due to restriction <10>

      ncalls       tottime  percall  cumtime  percall filename:lineno(function)
         359      4474.890   12.465 4474.890   12.465 {posix.waitpid}
329393/20019         6.653    0.000   19.739    0.001 /usr/lib/python2.7/sre_parse.py:395(_parse)
     7568367         4.649    0.000    5.419    0.000 /usr/lib/python2.7/sre_parse.py:193(__next)
502230/19911         3.076    0.000    8.468    0.000 /usr/lib/python2.7/sre_compile.py:64(_compile)
          14         2.469    0.176   32.667    2.333 {cPickle.load}
      486486         1.765    0.000    2.893    0.000 /usr/lib/python2.7/sre_compile.py:256(_optimize_charset)
     6588346         1.739    0.000    6.432    0.000 /usr/lib/python2.7/sre_parse.py:212(get)
21929242/21756251    1.243    0.000    1.279    0.000 {len}
629992/159215        1.177    0.000    1.435    0.000 /usr/lib/python2.7/sre_parse.py:151(getwidth)
    78541            1.113    0.000    1.113    0.000 {posix.remove}