Cython Malloc Benchmark

cython_malloc_benchmark.ipynb

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   "source": [
    "%load_ext cython"
   ]
  },
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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "\n",
    "import resource\n",
    "pagesize = resource.getpagesize()\n",
    "\n",
    "mem_size = int(1e9)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'1.17.0'"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "np.__version__"
   ]
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   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "%%cython\n",
    "\n",
    "from cpython.mem cimport PyMem_Malloc, PyMem_Realloc, PyMem_Free\n",
    "\n",
    "\n",
    "cdef class SomeMemory:\n",
    "\n",
    "    cdef unsigned char* data\n",
    "    cdef size_t nbytes\n",
    "\n",
    "    def __cinit__(self, size_t nbytes):\n",
    "        self.nbytes = nbytes\n",
    "        self.data = <unsigned char*> PyMem_Malloc(nbytes)\n",
    "        if not self.data:\n",
    "            raise MemoryError()\n",
    "    \n",
    "    def set_pages(self, size_t pagesize):\n",
    "        # We access one byte per page to ensure assignment\n",
    "        # of actual physical memory pages\n",
    "        for i in range(self.nbytes // pagesize):\n",
    "           self.data[i * pagesize] = 1\n",
    "    \n",
    "    def set_full(self):\n",
    "        for i in range(self.nbytes):\n",
    "           self.data[i] = 1\n",
    "\n",
    "    def __dealloc__(self):\n",
    "        PyMem_Free(self.data)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "mem = SomeMemory(mem_size)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "12.4 ms ± 780 µs per loop (mean ± std. dev. of 7 runs, 1 loop each)\n"
     ]
    }
   ],
   "source": [
    "%timeit mem.set_pages(pagesize)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "mem = SomeMemory(mem_size)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "283 ms ± 1.4 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)\n"
     ]
    }
   ],
   "source": [
    "%timeit mem.set_full()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "307 ms ± 59.9 µs per loop (mean ± std. dev. of 7 runs, 1 loop each)\n"
     ]
    }
   ],
   "source": [
    "%timeit x = np.ones(mem_size, dtype='u1')"
   ]
  }
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