and its microthreads to support massive concurrency pypy is the successor to the original psyco jitdescribed aheadand subsumes it with complete python implementation built for speed jit is really just an extension to the pvm--the rightmost bubble in figure - --that translates portions of your byte code all the way to binary machine code for faster execution it does this as your program is runningnot in prerun compile stepand is able to created type-specific machine code for the dynamic python language by keeping track of the data types of the objects your program processes by replacing portions of your byte code this wayyour program runs faster and faster as it is executing in additionsome python programs may also take up less memory under pypy at this writingpypy supports python code (not yet xand runs on intel (ia- and platforms (including windowslinuxand recent macs)with arm and ppc support under development it runs most cpython codethough extension modules must generally be recompiledand pypy has some minor but subtle language differencesincluding garbage collection semantics that obviate some common coding patterns for instanceits non-reference-count scheme means that temporary files may not close and flush output buffers immediatelyand may require manual close calls in some cases in returnyour code may run much quicker pypy currently claims speedup over cpython across range of benchmark programs (per casesits ability to take advantage of dynamic optimization opportunities can make python code as quick as codeand occasionally faster this is especially true for heavily algorithmic or numeric programswhich might otherwise be recoded in for instancein one simple benchmark we'll see in pypy today clocks in at faster than cpython and faster than cpython though other benchmarks will varysuch speedups may be compelling advantage in many domainsperhaps even more so than leading-edge language features just as importantmemory space is also optimized in pypy--in the case of one posted benchmarkrequiring mb and completing in secondscompared to cpython' mb and seconds pypy' tool chain is also general enough to support additional languagesincluding pyrologa prolog interpreter written in python using the pypy translator search for pypy' website for more pypy currently lives at search may also prove fruitful over time for an overview of its current performancealso see how python runs programs