dask_composite_task test

dask_composite_test.ipynb

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   "source": [
    "def task(x):\n",
    "    \"\"\" Sample single-process task that takes between 2 and 5 seconds \"\"\"\n",
    "    import time\n",
    "    import random\n",
    "    dt = random.uniform(2,5)\n",
    "    time.sleep(dt)\n",
    "    return x+dt\n",
    "\n",
    "def composite_task(np=8):\n",
    "    \"\"\" Composite task that runs multiple single-process runs in parallel \"\"\"\n",
    "    from functools import partial\n",
    "    from joblib import Parallel, delayed, parallel_backend\n",
    "    with parallel_backend('loky', n_jobs=np):\n",
    "        out=Parallel()(delayed(task)(i) for i in list(range(0, np)))\n",
    "    return out"
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      "3.61 s ± 0 ns per loop (mean ± std. dev. of 1 run, 7 loops each)\n"
     ]
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   "source": [
    "# Single-cpu task takes 3.5 seconds on average\n",
    "%timeit -n7 -r1 task(0)"
   ]
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      "5.03 s ± 0 ns per loop (mean ± std. dev. of 1 run, 1 loop each)\n"
     ]
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   "source": [
    "# This is bounded by the time of the longest task\n",
    "%timeit -n1 -r1 composite_task(8)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "from dask.distributed import Client, LocalCluster\n",
    "cluster = LocalCluster(n_workers=1, threads_per_worker=8, diagnostics_port = 8788)\n",
    "client = Client(cluster)"
   ]
  },
  {
   "cell_type": "code",
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   "metadata": {},
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      "25.5 s ± 0 ns per loop (mean ± std. dev. of 1 run, 1 loop each)\n"
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   "source": [
    "# This should take the same time as running a single composite task, but it doesn't - GIL is locked \n",
    "%timeit -n1 -r1 client.submit(composite_task,8).result()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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