142 lines
2.3 KiB
Markdown
142 lines
2.3 KiB
Markdown
<!--
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# Number of CPUs
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> Number of CPUs.
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<section class="usage">
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## Usage
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```javascript
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var NUM_CPUS = require( '@stdlib/os/num-cpus' );
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```
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#### NUM_CPUS
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Number of CPUs.
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```javascript
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var n = NUM_CPUS;
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// returns <number>
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```
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</section>
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<!-- /.usage -->
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<section class="notes">
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## Notes
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- In a web browser, the number of CPUs is determined by querying the hardware concurrency [API][hardware-concurrency].
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- Otherwise, the number of CPUs is determined via the [os][node-os] module.
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</section>
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<!-- /.notes -->
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<section class="examples">
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## Examples
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<!-- run-disable -->
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<!-- eslint-disable no-process-exit -->
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<!-- eslint no-undef: "error" -->
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```javascript
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var proc = require( 'process' );
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var cluster = require( 'cluster' );
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var NUM_CPUS = require( '@stdlib/os/num-cpus' );
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var i;
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function onTimeout() {
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proc.exit( 0 );
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}
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if ( cluster.isMaster ) {
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for ( i = 0; i < NUM_CPUS; i++ ) {
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cluster.fork();
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}
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} else {
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console.log( 'Worker %s. Process id: %d.', cluster.worker.id, cluster.worker.process.pid );
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setTimeout( onTimeout, 1000 );
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}
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```
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</section>
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<!-- /.examples -->
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* * *
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<section class="cli">
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## CLI
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<section class="usage">
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### Usage
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```text
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Usage: num-cpus [options]
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Options:
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-h, --help Print this message.
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-V, --version Print the package version.
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```
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</section>
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<!-- /.usage -->
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<section class="examples">
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### Examples
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```bash
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$ num-cpus
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<number>
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```
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</section>
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<!-- /.examples -->
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</section>
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<!-- /.cli -->
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<section class="links">
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[node-os]: https://nodejs.org/api/os.html#os_os_cpus
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[hardware-concurrency]: https://developer.mozilla.org/en-US/docs/Web/API/NavigatorConcurrentHardware/hardwareConcurrency
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</section>
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<!-- /.links -->
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