In [77]: cProfile.run('print(sum(file_block_count_lf(open(fn))))')
15496800
         10977 function calls in 6.479 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     1588    0.034    0.000    6.472    0.004 <ipython-input-76-8d8b0ada3387>:1(file_block_count_lf)
        1    0.000    0.000    6.479    6.479 <string>:1(<module>)
        1    0.000    0.000    0.000    0.000 _bootlocale.py:23(getpreferredencoding)
        1    0.000    0.000    0.000    0.000 codecs.py:251(__init__)
        1    0.000    0.000    0.000    0.000 codecs.py:300(__init__)
     2068    0.037    0.000    1.993    0.001 codecs.py:310(decode)
     2068    0.004    0.000    0.004    0.000 codecs.py:322(getstate)
        1    0.000    0.000    6.479    6.479 {built-in method exec}
        1    0.000    0.000    0.000    0.000 {built-in method nl_langinfo}
        1    0.000    0.000    0.000    0.000 {built-in method open}
        1    0.000    0.000    0.000    0.000 {built-in method print}
        1    0.006    0.006    6.478    6.478 {built-in method sum}
     2068    1.956    0.001    1.956    0.001 {built-in method utf_8_decode}
     1587    1.927    0.001    1.927    0.001 {method 'count' of 'str' objects}
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}
     1588    2.514    0.002    4.511    0.003 {method 'read' of '_io.TextIOWrapper' objects}

In [78]: def file_block_count_lf(f) :
    while True :
        k = f.read(1<<20)
        if k == '' :
            break
        yield k.count('\n')

In [79]: cProfile.run('for i,v in enumerate(open(fn)): pass\nprint(i)')
15496799
         406215 function calls in 10.868 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    9.675    9.675   10.868   10.868 <string>:1(<module>)
        1    0.000    0.000    0.000    0.000 _bootlocale.py:23(getpreferredencoding)
        1    0.000    0.000    0.000    0.000 codecs.py:251(__init__)
        1    0.000    0.000    0.000    0.000 codecs.py:300(__init__)
   203103    0.485    0.000    1.191    0.000 codecs.py:310(decode)
        1    0.000    0.000   10.868   10.868 {built-in method exec}
        1    0.000    0.000    0.000    0.000 {built-in method nl_langinfo}
        1    0.001    0.001    0.001    0.001 {built-in method open}
        1    0.000    0.000    0.000    0.000 {built-in method print}
   203103    0.706    0.000    0.706    0.000 {built-in method utf_8_decode}
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

In [78]: cProfile.run('print(sum(1 for l in open(fn)))')
15496800
         15903017 function calls in 14.557 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
 15496801    9.634    0.000   10.825    0.000 <string>:1(<genexpr>)
        1    0.000    0.000   14.557   14.557 <string>:1(<module>)
        1    0.000    0.000    0.000    0.000 _bootlocale.py:23(getpreferredencoding)
        1    0.000    0.000    0.000    0.000 codecs.py:251(__init__)
        1    0.000    0.000    0.000    0.000 codecs.py:300(__init__)
   203103    0.481    0.000    1.191    0.000 codecs.py:310(decode)
        1    0.000    0.000   14.557   14.557 {built-in method exec}
        1    0.000    0.000    0.000    0.000 {built-in method nl_langinfo}
        1    0.001    0.001    0.001    0.001 {built-in method open}
        1    0.000    0.000    0.000    0.000 {built-in method print}
        1    3.731    3.731   14.555   14.555 {built-in method sum}
   203103    0.710    0.000    0.710    0.000 {built-in method utf_8_decode}
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Pentium(R) Dual  CPU  E2180  @ 2.00GHz
stepping        : 13
microcode       : 0xa4
cpu MHz         : 1200.000
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dtherm
bugs            :
bogomips        : 3991.40
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Pentium(R) Dual  CPU  E2180  @ 2.00GHz
stepping        : 13
microcode       : 0xa4
cpu MHz         : 2000.000
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 1
cpu cores       : 2
apicid          : 1
initial apicid  : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dtherm
bugs            :
bogomips        : 3991.40
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

$ ls -l more_logs.txt
-rw-r--r-- 1 chris users 1663809100 Jan 18 21:18 more_logs.txt

$ python -V
Python 3.4.2