From 513eefcddc228b76b0bd4184c89bcba2e167477f Mon Sep 17 00:00:00 2001 From: Mark McGranaghan Date: Tue, 27 Dec 2016 10:32:33 -0800 Subject: [PATCH] Clarify worker-pool example Ref #131 --- examples/worker-pools/worker-pools.go | 9 +++--- examples/worker-pools/worker-pools.hash | 4 +-- examples/worker-pools/worker-pools.sh | 27 +++++++++--------- public/worker-pools | 38 +++++++++++++------------ 4 files changed, 41 insertions(+), 37 deletions(-) diff --git a/examples/worker-pools/worker-pools.go b/examples/worker-pools/worker-pools.go index 4aa5d69..1114a22 100644 --- a/examples/worker-pools/worker-pools.go +++ b/examples/worker-pools/worker-pools.go @@ -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 } } diff --git a/examples/worker-pools/worker-pools.hash b/examples/worker-pools/worker-pools.hash index 09eb260..013b2de 100644 --- a/examples/worker-pools/worker-pools.hash +++ b/examples/worker-pools/worker-pools.hash @@ -1,2 +1,2 @@ -9d5b1d008d278df7db7697d56d491d982da86e7d -y12QxBsKtT +1f9acf1e50be05cad73e6b085ed3294892c67d42 +RTRcHA05vV diff --git a/examples/worker-pools/worker-pools.sh b/examples/worker-pools/worker-pools.sh index 90937e1..10139fb 100644 --- a/examples/worker-pools/worker-pools.sh +++ b/examples/worker-pools/worker-pools.sh @@ -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 diff --git a/public/worker-pools b/public/worker-pools index 87cc85d..ba84dfe 100644 --- a/public/worker-pools +++ b/public/worker-pools @@ -40,7 +40,7 @@ a worker pool using goroutines and channels.

- + 
package main
@@ -73,8 +73,9 @@ 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
     }
 }
@@ -129,13 +130,13 @@ because there are no jobs yet.

         
         
           
-            
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)
@@ -151,7 +152,7 @@ channel to indicate that’s all the work we have.

           
           
 	        
-            
    for a := 1; a <= 9; a++ {
+            
    for a := 1; a <= 5; a++ {
         <-results
     }
 }
@@ -166,24 +167,25 @@ channel to indicate that’s all the work we have.

         
         
           
-            
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
 

 
           
@@ -195,7 +197,7 @@ there are 3 workers operating concurrently.

           
           
 	        
-            
real	0m3.149s
+            
real	0m2.358s