for the arm processorand still python -only implementation per its beta release notes"pypy is very compliant python interpreteralmost drop-in replacement for cpython it' fast due to its integrated tracing jit compiler this release supports machines running linux / mac os or windows it also supports arm machines running linux the claims seem accurate using the timing tools we'll study in pypy is often an order of magnitude (factor of faster than cpython and on tests 've runand sometimes even better this is despite the fact that pypy is -bit build on my windows test machinewhile cpython is faster -bit compile naturally the only benchmark that truly matters is your own codeand there are cases where cpython wins the racepypy' file iteratorsfor instancemay clock in slower today stillgiven pypy' focus on performance over language mutationand especially its support for the numeric domainmany today see pypy as an important path for python if you write cpu-intensive codepypy deserves your attention execution optimization tools cpython and most of the alternatives of the prior section all implement the python language in similar waysby compiling source code to byte code and executing the byte code on an appropriate virtual machine some systemssuch as the cython hybridthe shed skin +translatorand the just-in-time compilers in pypy and psyco instead attempt to optimize the basic execution model these systems are not required knowledge at this point in your python careerbut quick look at their place in the execution model might help demystify the model in general cythona python/ hybrid the cython system (based on work done by the pyrex projectis hybrid language that combines python code with the ability to call functions and use type declarations for variablesparametersand class attributes cython code can be compiled to code that uses the python/ apiwhich may then be compiled completely though not completely compatible with standard pythoncython can be useful both for wrapping external libraries and for coding efficient extensions for python see org for current status and details shed skina python-to- +translator shed skin is an emerging system that takes different approach to python program execution--it attempts to translate python source code to +codewhich your computer' +compiler then compiles to machine code as suchit represents platformneutral approach to running python code execution model variations