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The appropriate choice of tool will depend on the210task to be executed (CPU bound vs IO bound) and preferred style of211development (event driven cooperative multitasking vs preemptive212multitasking). Here’s an overview:</p>213<div class="toctree-wrapper compound">214<ul>215<li class="toctree-l1"><a class="reference internal" href="threading.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">threading</span></code> — Thread-based parallelism</a><ul>216<li class="toctree-l2"><a class="reference internal" href="threading.html#introduction">Introduction</a></li>217<li class="toctree-l2"><a class="reference internal" href="threading.html#gil-and-performance-considerations">GIL and performance considerations</a></li>218<li class="toctree-l2"><a class="reference internal" href="threading.html#reference">Reference</a><ul>219<li class="toctree-l3"><a class="reference internal" href="threading.html#thread-local-data">Thread-local data</a></li>220<li class="toctree-l3"><a class="reference internal" href="threading.html#thread-objects">Thread objects</a></li>221<li class="toctree-l3"><a class="reference internal" href="threading.html#lock-objects">Lock objects</a></li>222<li class="toctree-l3"><a class="reference internal" href="threading.html#rlock-objects">RLock objects</a></li>223<li class="toctree-l3"><a class="reference internal" href="threading.html#condition-objects">Condition objects</a></li>224<li class="toctree-l3"><a class="reference internal" href="threading.html#semaphore-objects">Semaphore objects</a></li>225<li class="toctree-l3"><a class="reference internal" href="threading.html#semaphore-example"><code class="xref py py-class docutils literal notranslate"><span class="pre">Semaphore</span></code> example</a></li>226<li class="toctree-l3"><a class="reference internal" href="threading.html#event-objects">Event objects</a></li>227<li class="toctree-l3"><a class="reference internal" href="threading.html#timer-objects">Timer objects</a></li>228<li class="toctree-l3"><a class="reference internal" href="threading.html#barrier-objects">Barrier objects</a></li>229</ul>230</li>231<li class="toctree-l2"><a class="reference internal" href="threading.html#using-locks-conditions-and-semaphores-in-the-with-statement">Using locks, conditions, and semaphores in the <code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code> statement</a></li>232</ul>233</li>234<li class="toctree-l1"><a class="reference internal" href="multiprocessing.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">multiprocessing</span></code> — Process-based parallelism</a><ul>235<li class="toctree-l2"><a class="reference internal" href="multiprocessing.html#introduction">Introduction</a><ul>236<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#the-process-class">The <code class="xref py py-class docutils literal notranslate"><span class="pre">Process</span></code> class</a></li>237<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#contexts-and-start-methods">Contexts and start methods</a></li>238<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#exchanging-objects-between-processes">Exchanging objects between processes</a></li>239<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#synchronization-between-processes">Synchronization between processes</a></li>240<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#sharing-state-between-processes">Sharing state between processes</a></li>241<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#using-a-pool-of-workers">Using a pool of workers</a></li>242</ul>243</li>244<li class="toctree-l2"><a class="reference internal" href="multiprocessing.html#reference">Reference</a><ul>245<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#global-start-method">Global start method</a></li>246<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#process-and-exceptions"><code class="xref py py-class docutils literal notranslate"><span class="pre">Process</span></code> and exceptions</a></li>247<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#pipes-and-queues">Pipes and Queues</a></li>248<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#miscellaneous">Miscellaneous</a></li>249<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#connection-objects">Connection Objects</a></li>250<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#synchronization-primitives">Synchronization primitives</a></li>251<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#shared-ctypes-objects">Shared <code class="xref py py-mod docutils literal notranslate"><span class="pre">ctypes</span></code> Objects</a><ul>252<li class="toctree-l4"><a class="reference internal" href="multiprocessing.html#module-multiprocessing.sharedctypes">The <code class="xref py py-mod docutils literal notranslate"><span class="pre">multiprocessing.sharedctypes</span></code> module</a></li>253</ul>254</li>255<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#managers">Managers</a><ul>256<li class="toctree-l4"><a class="reference internal" href="multiprocessing.html#customized-managers">Customized managers</a></li>257<li class="toctree-l4"><a class="reference internal" href="multiprocessing.html#using-a-remote-manager">Using a remote manager</a></li>258</ul>259</li>260<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#proxy-objects">Proxy Objects</a><ul>261<li class="toctree-l4"><a class="reference internal" href="multiprocessing.html#cleanup">Cleanup</a></li>262</ul>263</li>264<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#module-multiprocessing.pool">Process Pools</a></li>265<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#module-multiprocessing.connection">Listeners and Clients</a><ul>266<li class="toctree-l4"><a class="reference internal" href="multiprocessing.html#address-formats">Address Formats</a></li>267</ul>268</li>269<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#authentication-keys">Authentication keys</a></li>270<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#logging">Logging</a></li>271<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#module-multiprocessing.dummy">The <code class="xref py py-mod docutils literal notranslate"><span class="pre">multiprocessing.dummy</span></code> module</a></li>272</ul>273</li>274<li class="toctree-l2"><a class="reference internal" href="multiprocessing.html#programming-guidelines">Programming guidelines</a><ul>275<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#all-start-methods">All start methods</a></li>276<li class="toctree-l3"><a class="reference internal" href="multiprocessing.html#the-spawn-and-forkserver-start-methods">The <em>spawn</em> and <em>forkserver</em> start methods</a></li>277</ul>278</li>279<li class="toctree-l2"><a class="reference internal" href="multiprocessing.html#examples">Examples</a></li>280</ul>281</li>282<li class="toctree-l1"><a class="reference internal" href="multiprocessing.shared_memory.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">multiprocessing.shared_memory</span></code> — Shared memory for direct access across processes</a></li>283<li class="toctree-l1"><a class="reference internal" href="concurrent.html">The <code class="xref py py-mod docutils literal notranslate"><span class="pre">concurrent</span></code> package</a></li>284<li class="toctree-l1"><a class="reference internal" href="concurrent.futures.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">concurrent.futures</span></code> — Launching parallel tasks</a><ul>285<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#executor-objects">Executor Objects</a></li>286<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#threadpoolexecutor">ThreadPoolExecutor</a><ul>287<li class="toctree-l3"><a class="reference internal" href="concurrent.futures.html#threadpoolexecutor-example">ThreadPoolExecutor Example</a></li>288</ul>289</li>290<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#interpreterpoolexecutor">InterpreterPoolExecutor</a></li>291<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#processpoolexecutor">ProcessPoolExecutor</a><ul>292<li class="toctree-l3"><a class="reference internal" href="concurrent.futures.html#processpoolexecutor-example">ProcessPoolExecutor Example</a></li>293</ul>294</li>295<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#future-objects">Future Objects</a></li>296<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#module-functions">Module Functions</a></li>297<li class="toctree-l2"><a class="reference internal" href="concurrent.futures.html#exception-classes">Exception classes</a></li>298</ul>299</li>300<li class="toctree-l1"><a class="reference internal" href="concurrent.interpreters.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">concurrent.interpreters</span></code> — Multiple interpreters in the same process</a><ul>301<li class="toctree-l2"><a class="reference internal" href="concurrent.interpreters.html#key-details">Key details</a></li>302<li class="toctree-l2"><a class="reference internal" href="concurrent.interpreters.html#introduction">Introduction</a><ul>303<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#multiple-interpreters-and-isolation">Multiple Interpreters and Isolation</a></li>304<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#running-in-an-interpreter">Running in an Interpreter</a></li>305<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#concurrency-and-parallelism">Concurrency and Parallelism</a></li>306<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#communication-between-interpreters">Communication Between Interpreters</a></li>307<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#sharing-objects">“Sharing” Objects</a></li>308</ul>309</li>310<li class="toctree-l2"><a class="reference internal" href="concurrent.interpreters.html#reference">Reference</a><ul>311<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#interpreter-objects">Interpreter objects</a></li>312<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#exceptions">Exceptions</a></li>313<li class="toctree-l3"><a class="reference internal" href="concurrent.interpreters.html#communicating-between-interpreters">Communicating Between Interpreters</a></li>314</ul>315</li>316<li class="toctree-l2"><a class="reference internal" href="concurrent.interpreters.html#basic-usage">Basic usage</a></li>317</ul>318</li>319<li class="toctree-l1"><a class="reference internal" href="subprocess.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">subprocess</span></code> — Subprocess management</a><ul>320<li class="toctree-l2"><a class="reference internal" href="subprocess.html#using-the-subprocess-module">Using the <code class="xref py py-mod docutils literal notranslate"><span class="pre">subprocess</span></code> Module</a><ul>321<li class="toctree-l3"><a class="reference internal" href="subprocess.html#frequently-used-arguments">Frequently Used Arguments</a></li>322<li class="toctree-l3"><a class="reference internal" href="subprocess.html#popen-constructor">Popen Constructor</a></li>323<li class="toctree-l3"><a class="reference internal" href="subprocess.html#exceptions">Exceptions</a></li>324</ul>325</li>326<li class="toctree-l2"><a class="reference internal" href="subprocess.html#security-considerations">Security Considerations</a></li>327<li class="toctree-l2"><a class="reference internal" href="subprocess.html#popen-objects">Popen Objects</a></li>328<li class="toctree-l2"><a class="reference internal" href="subprocess.html#windows-popen-helpers">Windows Popen Helpers</a><ul>329<li class="toctree-l3"><a class="reference internal" href="subprocess.html#windows-constants">Windows Constants</a></li>330</ul>331</li>332<li class="toctree-l2"><a class="reference internal" href="subprocess.html#older-high-level-api">Older high-level API</a></li>333<li class="toctree-l2"><a class="reference internal" href="subprocess.html#replacing-older-functions-with-the-subprocess-module">Replacing Older Functions with the <code class="xref py py-mod docutils literal notranslate"><span class="pre">subprocess</span></code> Module</a><ul>334<li class="toctree-l3"><a class="reference internal" href="subprocess.html#replacing-bin-sh-shell-command-substitution">Replacing <strong class="program">/bin/sh</strong> shell command substitution</a></li>335<li class="toctree-l3"><a class="reference internal" href="subprocess.html#replacing-shell-pipeline">Replacing shell pipeline</a></li>336<li class="toctree-l3"><a class="reference internal" href="subprocess.html#replacing-os-system">Replacing <code class="xref py py-func docutils literal notranslate"><span class="pre">os.system()</span></code></a></li>337<li class="toctree-l3"><a class="reference internal" href="subprocess.html#replacing-the-os-spawn-family">Replacing the <code class="xref py py-func docutils literal notranslate"><span class="pre">os.spawn</span></code> family</a></li>338<li class="toctree-l3"><a class="reference internal" href="subprocess.html#replacing-os-popen">Replacing <code class="xref py py-func docutils literal notranslate"><span class="pre">os.popen()</span></code></a></li>339</ul>340</li>341<li class="toctree-l2"><a class="reference internal" href="subprocess.html#legacy-shell-invocation-functions">Legacy Shell Invocation Functions</a></li>342<li class="toctree-l2"><a class="reference internal" href="subprocess.html#notes">Notes</a><ul>343<li class="toctree-l3"><a class="reference internal" href="subprocess.html#timeout-behavior">Timeout Behavior</a></li>344<li class="toctree-l3"><a class="reference internal" href="subprocess.html#converting-an-argument-sequence-to-a-string-on-windows">Converting an argument sequence to a string on Windows</a></li>345<li class="toctree-l3"><a class="reference internal" href="subprocess.html#disable-use-of-posix-spawn">Disable use of <code class="docutils literal notranslate"><span class="pre">posix_spawn()</span></code></a></li>346</ul>347</li>348</ul>349</li>350<li class="toctree-l1"><a class="reference internal" href="sched.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">sched</span></code> — Event scheduler</a><ul>351<li class="toctree-l2"><a class="reference internal" href="sched.html#scheduler-objects">Scheduler Objects</a></li>352</ul>353</li>354<li class="toctree-l1"><a class="reference internal" href="queue.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code> — A synchronized queue class</a><ul>355<li class="toctree-l2"><a class="reference internal" href="queue.html#queue-objects">Queue Objects</a><ul>356<li class="toctree-l3"><a class="reference internal" href="queue.html#waiting-for-task-completion">Waiting for task completion</a></li>357<li class="toctree-l3"><a class="reference internal" href="queue.html#terminating-queues">Terminating queues</a></li>358</ul>359</li>360<li class="toctree-l2"><a class="reference internal" href="queue.html#simplequeue-objects">SimpleQueue Objects</a></li>361</ul>362</li>363<li class="toctree-l1"><a class="reference internal" href="contextvars.html"><code class="xref py py-mod docutils literal notranslate"><span class="pre">contextvars</span></code> — Context Variables</a><ul>364<li class="toctree-l2"><a class="reference internal" href="contextvars.html#context-variables">Context Variables</a></li>365<li class="toctree-l2"><a class="reference internal" href="contextvars.html#manual-context-management">Manual Context Management</a></li>366<li class="toctree-l2"><a class="reference internal" href="contextvars.html#asyncio-support">asyncio support</a></li>367</ul>368</li>369</ul>370</div>371<p>The following are support modules for some of the above services:</p>372<div class="toctree-wrapper compound">373<ul>374<li class="toctree-l1"><a class="reference internal" href="_thread.html"><code 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