cache_numba_func_ptr.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "4b503fb8-3649-46f3-9265-cb52f2f232ad",
   "metadata": {},
   "outputs": [],
   "source": [
    "\n",
    "import numpy as np\n",
    "import scipy.linalg.lapack\n",
    "import numba\n",
    "from numba.core import cgutils\n",
    "import pytensor.link.numba.dispatch.linalg._LAPACK\n",
    "import ctypes\n",
    "import scipy.special.cython_special\n",
    "from llvmlite import ir\n",
    "\n",
    "def _get_func_ptr_inner():\n",
    "    func = scipy.special.cython_special.psi\n",
    "    cfunc = pytensor.link.numba.dispatch.cython_support.wrap_cython_function(func, np.float64, [np.float64])\n",
    "    return cfunc._func_ptr\n",
    "\n",
    "@numba.njit\n",
    "def get_func_ptr():\n",
    "    with numba.objmode(ptr=numba.types.c_intp):\n",
    "        ptr = _get_func_ptr_inner()\n",
    "    return ptr\n",
    "\n",
    "@numba.extending.intrinsic(prefer_literal=True)\n",
    "def _call_cached_ptr(typingctx, get_ptr_func, func_type_ref):\n",
    "    func_type = func_type_ref.instance_type\n",
    "\n",
    "    def codegen(context, builder, signature, args):\n",
    "\n",
    "        ptr_ty = ir.PointerType(ir.IntType(8))\n",
    "        null = ptr_ty(None)\n",
    "\n",
    "        # Align to cache line\n",
    "        align = 64\n",
    "\n",
    "        mod = builder.module\n",
    "        var = cgutils.add_global_variable(mod, ptr_ty, \"_ptr_cache\")\n",
    "        var.align = align\n",
    "        #var.linkage = \"linkonce\"\n",
    "        var.linkage = \"private\"\n",
    "        var.initializer = null\n",
    "\n",
    "        var_val = builder.load_atomic(var, \"acquire\", align)\n",
    "        result_ptr = cgutils.alloca_once_value(builder, var_val)\n",
    "\n",
    "        with builder.if_then(builder.icmp_signed(\"==\", var_val, null), likely=False):\n",
    "            sig = typingctx.resolve_function_type(get_ptr_func, [], {})\n",
    "            func = context.get_function(get_ptr_func, sig)\n",
    "            new_ptr = func(builder, [])\n",
    "            new_ptr = builder.inttoptr(new_ptr, ptr_ty)\n",
    "            builder.store_atomic(new_ptr, var, \"release\", align)\n",
    "            builder.store(new_ptr, result_ptr)\n",
    "\n",
    "        sfunc = cgutils.create_struct_proxy(func_type)(context, builder)\n",
    "        sfunc.c_addr = builder.load(result_ptr)\n",
    "        return sfunc._getvalue()\n",
    "\n",
    "    sig = func_type(get_ptr_func, func_type_ref)\n",
    "    return sig, codegen\n",
    "\n",
    "func_type = numba.types.FunctionType(numba.float64(numba.float64, numba.int64))\n",
    "\n",
    "@numba.njit(cache=True)\n",
    "def foo(x, y):\n",
    "    func = _call_cached_ptr(get_func_ptr, func_type)\n",
    "    return func(x, y)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "612b9880-0d44-42b1-ab51-318f848947bd",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "186 ns ± 2.12 ns per loop (mean ± std. dev. of 7 runs, 10,000,000 loops each)\n"
     ]
    }
   ],
   "source": [
    "%timeit foo(0.1, 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "50e46b69-9b5a-413b-bc4e-ee91be10492b",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "-10.423754940411076"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "foo(0.1, 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d1e4552a-3566-4cd5-9f41-04a4a44bd96c",
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python (Pixi)",
   "language": "python",
   "name": "pixi-kernel-python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.13.9"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 5
}