blocks|key|1196096|text|不，没有，除非你使用一些ActiveX。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1196097|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

No, there isn't, unless you use some ActiveX.

blocks|key|981697|text|您可以尝试使用以下命令估计内核的数量：https://github.com/oftn/core-estimator|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|981698|演示：http://eligrey.com/blog/post/cpu-core-estimation-with-javascript|981699|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/oftn/core-estimator|1|http://eligrey.com/blog/post/cpu-core-estimation-with-javascript^0|J|12|0|0|3|1S|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@$A|U|B|V|1|W]]|C|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]|N|$5|I|J|K|C|$L|O]]]]

You can try to estimate the number of cores with:
<a href="https://github.com/oftn/core-estimator" rel="noreferrer">https://github.com/oftn/core-estimator</a>

demo:
<a href="http://eligrey.com/blog/post/cpu-core-estimation-with-javascript" rel="noreferrer">http://eligrey.com/blog/post/cpu-core-estimation-with-javascript</a>

blocks|key|981759|text|这是我拼凑出来的一个相当快速的并发估计器...它还没有经过太多的测试：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|981760|http://jsfiddle.net/Ma4YT/2/|offset|length|981761|下面是workers运行的代码(因为我有一个jsfiddle链接，所以需要一个示例)：|981762|//+create+worker+concurrency+estimation+code+as+blob
var+blobUrl+=+URL.createObjectURL(new+Blob(['(',
++function()+{
++++self.addEventListener('message',+function(e)+{
++++++//+run+worker+for+4+ms
++++++var+st+=+Date.now();
++++++var+et+=+st+%2B+4;
++++++while(Date.now()+<+et);
++++++self.postMessage({st:+st,+et:+et});
++++});
++}.toString(),
')()'],+{type:+'application/javascript'}));|code-block|syntax|javascript|981763|估计器有大量的Worker在短时间内(4ms)运行，并报告他们运行的时间(不幸的是，performance.now()在Web+Worker中不可用以获得更准确的计时)。然后，主线程检查以查看在同一时间内运行的工作线程的最大数量。这个测试被重复多次，以获得一个像样的样本来产生估计值。|981764|因此，主要的想法是，给定足够小的工作量，只有在有足够的内核支持该行为的情况下，才应该安排工人同时运行。这显然只是一个估计，但到目前为止，对于我测试过的几台机器来说，它是相当准确的--这对于我的用例来说已经足够好了。可以增加样本数量以获得更准确的近似值；我只使用10，因为它很快，我不想浪费时间进行估计，而不是仅仅完成工作。|981765|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|S|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Y|8|@]|9|@$D|Z|E|10|1|11]]|A|$]]|$1|F|3|G|5|6|7|12|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|13|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|14|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|15|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|C]]]]

Here's a fairly quick concurrency estimator I hacked together... it hasn't undergone much testing yet:

<a href="http://jsfiddle.net/Ma4YT/2/" rel="noreferrer">http://jsfiddle.net/Ma4YT/2/</a>

Here's the code the workers run (since I have a jsfiddle link a sample is necessary):

<pre><code>
// create worker concurrency estimation code as blob
var blobUrl = URL.createObjectURL(new Blob(['(',
 function() {
 self.addEventListener('message', function(e) {
 // run worker for 4 ms
 var st = Date.now();
 var et = st + 4;
 while(Date.now() &lt; et);
 self.postMessage({st: st, et: et});
 });
 }.toString(),
')()'], {type: 'application/javascript'}));
</code></pre>

The estimator has a large number of workers run for a short period of time (4ms) and report back the times that they ran (unfortunately, performance.now() is unavailable in Web Workers for more accurate timing). The main thread then checks to see the maximum number of workers that were running during the same time. This test is repeated a number of times to get a decent sample to produce an estimate with.

So the main idea is that, given a small enough chunk of work, workers should only be scheduled to run at the same time if there are enough cores to support that behavior. It's obviously just an estimate, but so far it's been reasonably accurate for a few machines I've tested -- which is good enough for my use case. The number of samples can be increased to get a more accurate approximation; I just use 10 because it's quick and I don't want to waste time estimating versus just getting the work done.

blocks|key|981829|text|如果您要对工作人员进行数据处理，navigator.hardwareConcurrency可能不够好，因为它返回现代浏览器中的逻辑核心数，您可以尝试使用WebCPU估计物理核心数|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|981830|import+{WebCPU}+from+'webcpu';

WebCPU.detectCPU().then(result+=>+{
++++console.log(`Reported+Cores:+${result.reportedCores}`);
++++console.log(`Estimated+Idle+Cores:+${result.estimatedIdleCores}`);
++++console.log(`Estimated+Physical+Cores:+${result.estimatedPhysicalCores}`);
});|code-block|syntax|javascript|981831|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/darionco/WebCPU^0|G|T|24|6|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

If you are going to do data crunching on your workers, <code>navigator.hardwareConcurrency</code> might not be good enough as it returns the number of logical cores in modern browsers, you could try to estimate the number of physical cores using <a href="https://github.com/darionco/WebCPU" rel="nofollow noreferrer">WebCPU</a>:

<pre><code>import {WebCPU} from 'webcpu';

WebCPU.detectCPU().then(result =&gt; {
 console.log(`Reported Cores: ${result.reportedCores}`);
 console.log(`Estimated Idle Cores: ${result.estimatedIdleCores}`);
 console.log(`Estimated Physical Cores: ${result.estimatedPhysicalCores}`);
});
</code></pre>

Is there a way to determine the number of available CPU cores in JavaScript, so that you could adjust the number of web workers depending on that?

Get number of CPU cores in JavaScript?

有没有一种方法可以确定JavaScript中可用CPU核心的数量，以便您可以根据该数量调整web worker的数量？

问获取JavaScript中的CPU核数？
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