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Clarify worker-pool example

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Ref #131
This commit is contained in:
Mark McGranaghan 2016-12-27 10:32:33 -08:00
parent 6a58750728
commit 513eefcddc
4 changed files with 41 additions and 37 deletions
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9
examples/worker-pools/worker-pools.go
View File

@ -13,8 +13,9 @@ import "time"
// simulate an expensive task.
func worker(id int, jobs <-chan int, results chan<- int) {
for j := range jobs {
fmt.Println("worker", id, "processing job", j)
fmt.Println("worker", id, "started job", j)
time.Sleep(time.Second)
fmt.Println("worker", id, "finished job", j)
results <- j * 2
}
}
@ -33,15 +34,15 @@ func main() {
go worker(w, jobs, results)
}
// Here we send 9 `jobs` and then `close` that
// Here we send 5 `jobs` and then `close` that
// channel to indicate that's all the work we have.
for j := 1; j <= 9; j++ {
for j := 1; j <= 5; j++ {
jobs <- j
}
close(jobs)
// Finally we collect all the results of the work.
for a := 1; a <= 9; a++ {
for a := 1; a <= 5; a++ {
<-results
}
}

4
examples/worker-pools/worker-pools.hash
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@ -1,2 +1,2 @@
9d5b1d008d278df7db7697d56d491d982da86e7d
y12QxBsKtT
1f9acf1e50be05cad73e6b085ed3294892c67d42
RTRcHA05vV

27
examples/worker-pools/worker-pools.sh
View File

@ -1,16 +1,17 @@
# Our running program shows the 9 jobs being executed by
# various workers. The program only takes about 3 seconds
# despite doing about 9 seconds of total work because
# Our running program shows the 5 jobs being executed by
# various workers. The program only takes about 2 seconds
# despite doing about 5 seconds of total work because
# there are 3 workers operating concurrently.
$ time go run worker-pools.go
worker 1 processing job 1
worker 2 processing job 2
worker 3 processing job 3
worker 1 processing job 4
worker 2 processing job 5
worker 3 processing job 6
worker 1 processing job 7
worker 2 processing job 8
worker 3 processing job 9
worker 1 started job 1
worker 2 started job 2
worker 3 started job 3
worker 1 finished job 1
worker 1 started job 4
worker 2 finished job 2
worker 2 started job 5
worker 3 finished job 3
worker 1 finished job 4
worker 2 finished job 5
real 0m3.149s
real 0m2.358s

38
public/worker-pools
View File

@ -40,7 +40,7 @@ a <em>worker pool</em> using goroutines and channels.</p>
</td>
<td class="code leading">
<a href="http://play.golang.org/p/y12QxBsKtT"><img title="Run code" src="play.png" class="run" /></a>
<a href="http://play.golang.org/p/RTRcHA05vV"><img title="Run code" src="play.png" class="run" /></a>
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div>
@ -73,8 +73,9 @@ simulate an expensive task.</p>
<div class="highlight"><pre><span class="kd">func</span> <span class="nx">worker</span><span class="p">(</span><span class="nx">id</span> <span class="kt">int</span><span class="p">,</span> <span class="nx">jobs</span> <span class="o">&lt;-</span><span class="kd">chan</span> <span class="kt">int</span><span class="p">,</span> <span class="nx">results</span> <span class="kd">chan</span><span class="o">&lt;-</span> <span class="kt">int</span><span class="p">)</span> <span class="p">{</span>
<span class="k">for</span> <span class="nx">j</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">jobs</span> <span class="p">{</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;worker&quot;</span><span class="p">,</span> <span class="nx">id</span><span class="p">,</span> <span class="s">&quot;processing job&quot;</span><span class="p">,</span> <span class="nx">j</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;worker&quot;</span><span class="p">,</span> <span class="nx">id</span><span class="p">,</span> <span class="s">&quot;started job&quot;</span><span class="p">,</span> <span class="nx">j</span><span class="p">)</span>
<span class="nx">time</span><span class="p">.</span><span class="nx">Sleep</span><span class="p">(</span><span class="nx">time</span><span class="p">.</span><span class="nx">Second</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="s">&quot;worker&quot;</span><span class="p">,</span> <span class="nx">id</span><span class="p">,</span> <span class="s">&quot;finished job&quot;</span><span class="p">,</span> <span class="nx">j</span><span class="p">)</span>
<span class="nx">results</span> <span class="o">&lt;-</span> <span class="nx">j</span> <span class="o">*</span> <span class="mi">2</span>
<span class="p">}</span>
<span class="p">}</span>
@ -129,13 +130,13 @@ because there are no jobs yet.</p>
<tr>
<td class="docs">
<p>Here we send 9 <code>jobs</code> and then <code>close</code> that
<p>Here we send 5 <code>jobs</code> and then <code>close</code> that
channel to indicate that&rsquo;s all the work we have.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">j</span> <span class="o">:=</span> <span class="mi">1</span><span class="p">;</span> <span class="nx">j</span> <span class="o">&lt;=</span> <span class="mi">9</span><span class="p">;</span> <span class="nx">j</span><span class="o">++</span> <span class="p">{</span>
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">j</span> <span class="o">:=</span> <span class="mi">1</span><span class="p">;</span> <span class="nx">j</span> <span class="o">&lt;=</span> <span class="mi">5</span><span class="p">;</span> <span class="nx">j</span><span class="o">++</span> <span class="p">{</span>
<span class="nx">jobs</span> <span class="o">&lt;-</span> <span class="nx">j</span>
<span class="p">}</span>
<span class="nb">close</span><span class="p">(</span><span class="nx">jobs</span><span class="p">)</span>
@ -151,7 +152,7 @@ channel to indicate that&rsquo;s all the work we have.</p>
</td>
<td class="code">
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">a</span> <span class="o">:=</span> <span class="mi">1</span><span class="p">;</span> <span class="nx">a</span> <span class="o">&lt;=</span> <span class="mi">9</span><span class="p">;</span> <span class="nx">a</span><span class="o">++</span> <span class="p">{</span>
<div class="highlight"><pre> <span class="k">for</span> <span class="nx">a</span> <span class="o">:=</span> <span class="mi">1</span><span class="p">;</span> <span class="nx">a</span> <span class="o">&lt;=</span> <span class="mi">5</span><span class="p">;</span> <span class="nx">a</span><span class="o">++</span> <span class="p">{</span>
<span class="o">&lt;-</span><span class="nx">results</span>
<span class="p">}</span>
<span class="p">}</span>
@ -166,24 +167,25 @@ channel to indicate that&rsquo;s all the work we have.</p>
<tr>
<td class="docs">
<p>Our running program shows the 9 jobs being executed by
various workers. The program only takes about 3 seconds
despite doing about 9 seconds of total work because
<p>Our running program shows the 5 jobs being executed by
various workers. The program only takes about 2 seconds
despite doing about 5 seconds of total work because
there are 3 workers operating concurrently.</p>
</td>
<td class="code leading">
<div class="highlight"><pre><span class="gp">$</span> <span class="nb">time</span> go run worker-pools.go
<span class="go">worker 1 processing job 1</span>
<span class="go">worker 2 processing job 2</span>
<span class="go">worker 3 processing job 3</span>
<span class="go">worker 1 processing job 4</span>
<span class="go">worker 2 processing job 5</span>
<span class="go">worker 3 processing job 6</span>
<span class="go">worker 1 processing job 7</span>
<span class="go">worker 2 processing job 8</span>
<span class="go">worker 3 processing job 9</span>
<span class="go">worker 1 started job 1</span>
<span class="go">worker 2 started job 2</span>
<span class="go">worker 3 started job 3</span>
<span class="go">worker 1 finished job 1</span>
<span class="go">worker 1 started job 4</span>
<span class="go">worker 2 finished job 2</span>
<span class="go">worker 2 started job 5</span>
<span class="go">worker 3 finished job 3</span>
<span class="go">worker 1 finished job 4</span>
<span class="go">worker 2 finished job 5</span>
</pre></div>
</td>
@ -195,7 +197,7 @@ there are 3 workers operating concurrently.</p>
</td>
<td class="code">
<div class="highlight"><pre><span class="go">real 0m3.149s</span>
<div class="highlight"><pre><span class="go">real 0m2.358s</span>
</pre></div>
</td>