I/O performance

[krizhanovsky]

tls.test_tls_handshake.TlsHandshakeTest.test_fuzzing is an example of relatively long test and profiling tool (#119) show following statistics:

   Ordered by: internal time
   List reduced from 843 to 20 due to restriction <20>

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
      110   20.027    0.182   20.027    0.182 {method 'recv' of '_socket.socket' objects}
1113586/1098106    1.764    0.000    3.028    0.000 packet.py:206(__setattr__)
295017/121497    0.951    0.000    2.104    0.000 copy.py:145(deepcopy)
561571/535007    0.868    0.000    1.300    0.000 packet.py:189(setfieldval)
52383/32683    0.829    0.000    7.338    0.000 packet.py:68(__init__)
483246/3180    0.798    0.000    0.798    0.000 ec.py:7(egcd)
   225017    0.474    0.000    0.514    0.000 copy.py:267(_keep_alive)
106366/32683    0.415    0.000    7.544    0.000 base_classes.py:192(__call__)
    52383    0.381    0.000    2.491    0.000 packet.py:100(do_init_fields)
   545327    0.339    0.000    0.339    0.000 packet.py:1105(setfieldval)
    25637    0.333    0.000    4.634    0.000 packet.py:653(clone_with)
86570/38236    0.328    0.000    5.173    0.000 packet.py:671(loop)
17690/3610    0.288    0.000    3.528    0.001 packet.py:145(copy)
104344/60454    0.285    0.000    3.480    0.000 packet.py:304(copy_fields_dict)
202293/105803    0.270    0.000    3.305    0.000 packet.py:307(<genexpr>)
    25637    0.230    0.000    0.267    0.000 packet.py:670(__iter__)
32816/1559    0.226    0.000    6.448    0.004 packet.py:309(self_build)
       26    0.208    0.008    0.208    0.008 {built-in method poll}
138676/72646    0.204    0.000    3.145    0.000 packet.py:302(copy_field_value)
       60    0.187    0.003    0.189    0.003 fuzzer.py:39(record)
.....
----------------------------------------------------------------------
Ran 1 test in 35.049s

OK

The test runs for 35 seconds and 20 of them are spent in recv() call which takes timeout=0.5 as a parameter. The problem was discussed in #103 (comment) and #103 (comment) , but with #118 (Debug mode for tests configuration) in mind (the rto parameter for TlsHandshake was introduced to be able to read data from Tempesta in debug mode) it's not easy to fix.

See also comments from commit e88af89 : helpers/remote.py and helpers/analyzer.py also struggle from the timeouts and can be reworked in event-driven fashion.

See and fix also TODO #120 comments around the code.