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| = Malloc Replacements = This page describes possible malloc replacements to be used for memory management in SAGE which is not directly controlled by Python such as manual malloc/realloc calls, the GMP library etc.. == Introduction == * Benchmarks performed on my ([[MartinAlbrecht|malb]]) 1200 Mhz Pentium 3 notebook running vanilla SAGE 1.4 == malloc == * "By default GMP uses malloc, realloc and free for memory allocation, and if they fail GMP prints a message to the standard error output and terminates the program." (http://www.swox.com/gmp/manual/Custom-Allocation.html) * GPL {{{#!python sage: x = 3; y = 5 sage: timeit _ = x + y 100000 loops, best of 3: 7.37 mircoseconds per loop }}} == PyMem_Malloc == The Python memory manager does keep track of some previous allocated, unused, but not yet freed blocks so it should be faster than malloc itself. It is currently used in GMP and Pyrex code in SAGE. == OMalloc == * GPLed (not announced yet) * faster than malloc/PyMem_Malloc etc. {{{#!python sage: x = 3; y = 5 # malloc (GMP default) sage: timeit _ = x + y 100000 loops, best of 3: 8.14 microseconds per loop sage: timeit _ = x + y 100000 loops, best of 3: 8.05 microseconds per loop sage: sage.rings.integer.pmem_malloc() sage: timeit _ = x + y # PyMem_Malloc 100000 loops, best of 3: 8.27 microseconds per loop sage: x = 3; y = 5 sage: timeit _ = x + y 100000 loops, best of 3: 8.21 microseconds per loop sage: omalloc_malloc() sage: timeit _ = x + y # omalloc 100000 loops, best of 3: 7.55 microseconds per loop sage: timeit _ = x + y 100000 loops, best of 3: 7.55 microseconds per loop }}} Larger integers: {{{#!python sage: x = 45234723458934634056310653251305043576435013985134515643531450714359863148659136951369851836545643565 sage: y = 23423964523462384234234234872345623645623452345283548234652365482348562346523642348263486234954534554 sage: timeit _ = x + y #malloc 100000 loops, best of 3: 8.3 microseconds per loop sage: sage.rings.integer.pmem_malloc() sage: timeit _ = x + y #PyMem_Malloc 100000 loops, best of 3: 8.58 microseconds per loop sage: omalloc_malloc() sage: timeit _ = x + y # omalloc 100000 loops, best of 3: 7.58 microseconds per loop }}} == DLMalloc == * LGPL * used by OMalloc * unsure what it does == default libCF Memory Manager == * GPL * seems to be faster for Integer addition than Python's manager {{{#!python sage: from sage.memory import * #only in my (malb) working copy # PyMem_Malloc sage: x = 5; y = 3 sage: %timeit _ = x+y 100000 loops, best of 3: 8.15 microseconds per loop # default libCF memory manager sage: memman_malloc() sage: %timeit _ = x+y 100000 loops, best of 3: 7.36 microseconds per loop }}} == libCF new Memory Manager == * GPL * crashed on me ([[MartinAlbrecht|malb]]) when trying to use it from withing SAGE == GivMM == * GPL * "Short description of the Givaro memory mechanism: each request of sz bytes returns the smallest bloc that contains at least sz bytes. Each bloc begins by a private data used to store size information or a pointer. All free blocs are linked in list. The allocation algorithm search in the corresponding list a free bloc, before call the system "malloc" routine. 512 different sizes of bloc are predefined. The maximum bloc size is 8054880 bytes. For higher bloc, the manager directly call malloc/free of the underlaying system." * Seems to be slower than PyMem_Malloc for Integer addition {{{#!python sage: from sage.memory import * sage: x = 5; y = 3 # PyMem_Malloc sage: %timeit _ = x+y 100000 loops, best of 3: 8.15 microseconds per loop # GivaroMM sage: givaro_malloc() sage: %timeit _ = x+y 100000 loops, best of 3: 8.36 microseconds per loop }}} |
