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18 KiB
JavaScript
1 line
18 KiB
JavaScript
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"use strict";(self.webpackChunkspeice_io=self.webpackChunkspeice_io||[]).push([["7848"],{76330:function(e,n,t){t.r(n),t.d(n,{assets:function(){return l},contentTitle:function(){return o},default:function(){return d},frontMatter:function(){return a},metadata:function(){return i},toc:function(){return c}});var i=t(26160),s=t(85893),r=t(50065);let a={slug:"2019/12/release-the-gil",title:"Release the GIL",date:new Date("2019-12-14T12:00:00.000Z"),authors:["bspeice"],tags:[]},o=void 0,l={authorsImageUrls:[void 0]},c=[{value:"Cython",id:"cython",level:2},{value:"Numba",id:"numba",level:2},{value:"Conclusion",id:"conclusion",level:2}];function h(e){let n={a:"a",blockquote:"blockquote",code:"code",em:"em",h2:"h2",li:"li",p:"p",pre:"pre",strong:"strong",ul:"ul",...(0,r.a)(),...e.components};return(0,s.jsxs)(s.Fragment,{children:[(0,s.jsxs)(n.p,{children:["Complaining about the ",(0,s.jsx)(n.a,{href:"https://wiki.python.org/moin/GlobalInterpreterLock",children:"Global Interpreter Lock"}),"\n(GIL) seems like a rite of passage for Python developers. It's easy to criticize a design decision\nmade before multi-core CPU's were widely available, but the fact that it's still around indicates\nthat it generally works ",(0,s.jsx)(n.a,{href:"https://wiki.c2.com/?PrematureOptimization",children:"Good"}),"\n",(0,s.jsx)(n.a,{href:"https://wiki.c2.com/?YouArentGonnaNeedIt",children:"Enough"}),". Besides, there are simple and effective\nworkarounds; it's not hard to start a\n",(0,s.jsx)(n.a,{href:"https://docs.python.org/3/library/multiprocessing.html",children:"new process"})," and use message passing to\nsynchronize code running in parallel."]}),"\n",(0,s.jsxs)(n.p,{children:["Still, wouldn't it be nice to have more than a single active interpreter thread? In an age of\nasynchronicity and ",(0,s.jsx)(n.em,{children:"M:N"})," threading, Python seems lacking. The ideal scenario is to take advantage of\nboth Python's productivity and the modern CPU's parallel capabilities."]}),"\n",(0,s.jsxs)(n.p,{children:["Presented below are two strategies for releasing the GIL's icy grip without giving up on what makes\nPython a nice language to start with. Bear in mind: these are just the tools, no claim is made about\nwhether it's a good idea to use them. Very often, unlocking the GIL is an\n",(0,s.jsx)(n.a,{href:"https://en.wikipedia.org/wiki/XY_problem",children:"XY problem"}),"; you want application performance, and the\nGIL seems like an obvious bottleneck. Remember that any gains from running code in parallel come at\nthe expense of project complexity; messing with the GIL is ultimately messing with Python's memory\nmodel."]}),"\n",(0,s.jsx)(n.pre,{children:(0,s.jsx)(n.code,{className:"language-python",children:"%load_ext Cython\nfrom numba import jit\n\nN = 1_000_000_000\n"})}),"\n",(0,s.jsx)(n.h2,{id:"cython",children:"Cython"}),"\n",(0,s.jsxs)(n.p,{children:["Put simply, ",(0,s.jsx)(n.a,{href:"https://cython.org/",children:"Cython"})," is a programming language that looks a lot like Python,\ngets ",(0,s.jsx)(n.a,{href:"https://en.wikipedia.org/wiki/Source-to-source_compiler",children:"transpiled"})," to C/C++, and integrates\nwell with the ",(0,s.jsx)(n.a,{href:"https://en.wikipedia.org/wiki/CPython",children:"CPython"})," API. It's great for building Python\nwrappers to C and C++ libraries, writing optimized code for numerical processing, and tons more. And\nwhen it comes to managing the GIL, there are two special features:"]}),"\n",(0,s.jsxs)(n.ul,{children:["\n",(0,s.jsxs)(n.li,{children:["The ",(0,s.jsx)(n.code,{children:"nogil"}),"\n",(0,s.jsx)(n.a,{href:"https://cython.readthedocs.io/en/latest/src/userguide/external_C_code.html#declaring-a-function-as-callable-without-the-gil",children:"function annotation"}),"\nasserts that a Cython function is safe to use without the GIL, and compilation will fail if it\ninteracts with Python in an unsafe manner"]}),"\n",(0,s.jsxs)(n.li,{children:["The ",(0,s.jsx)(n.code,{children:"with nogil"}),"\n",(0,s.jsx)(n.a,{href:"https://cython.readthedocs.io/en/latest/src/userguide/external_C_code.html#releasing-th
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