[pypy-dev] ctypes - PyPy 1.8 slower than Python 2.6.5
Sébastien Volle
sebastien.volle at gmail.com
Mon Feb 20 12:59:26 CET 2012
Hello Antonio,
Thank you for the update. I'll try and run a long running capture. Several
days worth of ARP packets should be enough to maximize JIT effect I suppose.
I'll keep you updated.
Regards,
Sébastien
Le 20 février 2012 12:05, Antonio Cuni <anto.cuni at gmail.com> a écrit :
> Hello Sébastien,
>
> I worked a bit on the pypy implementation of ctypes today, and now it is
> possible to pass ctypes arrays as parameters without leaving the fast path.
> The benchmark is still slower on PyPy, but not as much as before. Here are
> the results on my machine for running arp.py:
>
> cpython 2.7.2: 224 ms
> pypy-c 1.8: 1059 ms
> pypy-c trunk: 696 ms
>
> so, we are about 50% faster than before, although still slower than
> CPython.
> However, 224 ms is definitely too short for the JIT to warm up, so it
> would be nice if you could rerun the benchmark with a larger capture file.
>
> It's not necessary to retranslate pypy: you can just download pypy 1.8 and
> put the binary inside an updated copy of the mercurial repo (the relevant
> checkin is 6566e81c76a8).
>
> thank you!
> ciao,
> Anto
>
>
> On 02/13/2012 01:33 PM, Sébastien Volle wrote:
>
>> Hi all,
>>
>> My team is working on a project of fast packet sniffers and I'm comparing
>> performance between different languages.
>> So, we came up with a simple ARP sniffer that I ported to Python using
>> ctypes.
>>
>> During my investigations, I turned out that using ctypes, PyPy 1.8 is
>> 4x slower than CPython 2.6.5.
>> After looking at the PyPy buglist, it's seems there are couple open issues
>> about ctypes so I figured I would ask you guys first before filing a new
>> bug.
>>
>> I'm pretty new to ctypes and pypy so I'm not sure I understand what's
>> going.
>> My program seems to spend a lot of time in ctypes/function.py:_convert_**
>> args
>> though, has the following profile trace demonstrates:
>>
>> $ pypy -m cProfile -s time arp.py
>> Packet buffer now at 0x9CCECB2
>> Capture started
>> elapsed time : 3983.84ms
>> Total packets : 35571
>> packets/s : 8928.81
>>
>> 7839198 function calls (7838340 primitive calls) in 4.105 seconds
>>
>> Ordered by: internal time
>>
>> ncalls tottime percall cumtime percall filename:lineno(function)
>> 69876 0.546 0.000 1.584 0.000
>> function.py:480(_convert_args)
>> 214696 0.256 0.000 0.429 0.000 structure.py:236(_subarray)
>> 1052195 0.206 0.000 0.206 0.000 {isinstance}
>> 632437 0.192 0.000 0.192 0.000 {method 'append' of 'list'
>> objects}
>> 175326 0.187 0.000 0.407 0.000
>> function.py:350(_call_funcptr)
>> 1 0.173 0.173 4.105 4.105 arp.py:1(<module>)
>> 209628 0.158 0.000 0.587 0.000 primitive.py:272(from_param)
>> 214696 0.149 0.000 0.963 0.000 structure.py:90(__get__)
>> 71144 0.143 0.000 0.198 0.000 structure.py:216(__new__)
>> 106713 0.130 0.000 0.208 0.000 array.py:70(_CData_output)
>> 105450 0.124 0.000 2.281 0.000 function.py:689(__call__)
>> 69876 0.123 0.000 1.943 0.000 function.py:278(__call__)
>> 321412 0.102 0.000 0.102 0.000 {method 'fromaddress' of
>> 'Array' objects}
>> 209628 0.088 0.000 0.811 0.000 function.py:437(_conv_param)
>> 179125 0.083 0.000 0.083 0.000 {method 'fieldaddress' of
>> 'StructureInstance' objects}
>> 69883 0.080 0.000 0.122 0.000 primitive.py:308(__init__)
>> 71142 0.076 0.000 0.320 0.000
>> structure.py:174(from_address)
>> 105450 0.075 0.000 0.145 0.000
>> function.py:593(_build_result)
>> 139755 0.072 0.000 0.120 0.000
>> primitive.py:64(generic_xxx_p_**from_param)
>> 107983 0.070 0.000 0.125 0.000 basics.py:60(_CData_output)
>> 209828 0.062 0.000 0.062 0.000 {method 'get' of 'dict'
>> objects}
>> 107986 0.055 0.000 0.055 0.000 {method '__new__' of
>> '_ctypes.primitive.SimpleType' objects}
>> 71142 0.052 0.000 0.372 0.000 pointer.py:77(getcontents)
>> 35578 0.052 0.000 0.125 0.000 pointer.py:62(__init__)
>> 35576 0.050 0.000 0.062 0.000 pointer.py:83(setcontents)
>> 106713 0.047 0.000 0.047 0.000 {method '__new__' of
>> '_ctypes.array.ArrayMeta' objects}
>> 139750 0.043 0.000 0.181 0.000 primitive.py:84(from_param_
>> **void_p)
>> 209625 0.043 0.000 0.691 0.000 basics.py:50(get_ffi_param)
>> 283592/283435 0.041 0.000 0.041 0.000 {len}
>> 71144 0.040 0.000 0.040 0.000 {method '__new__' of
>> '_ctypes.structure.**StructOrUnionMeta' objects}
>> 105450 0.039 0.000 0.039 0.000 {method 'free_temp_buffers' of
>> '_ffi.FuncPtr' objects}
>> 176683 0.037 0.000 0.037 0.000 {hasattr}
>> 35571 0.037 0.000 0.423 0.000 pcap.py:89(next)
>>
>>
>> Anyway, I attached my full project to this mail, including a sample pcap
>> capture file. It requires libpcap to be installed on your system. Run
>> arp.py
>> to run the sniffer on the included demo.pcap capture file.
>> I realize I should try and narrow down the issue some more, but I can't
>> really
>> afford to spend too much time on this right now so hopefully, this will
>> be a
>> least a bit helpful.
>>
>> Thanks!
>>
>> Regards,
>> Sébastien
>>
>>
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