Refactoring of test code

examples/Makefile

@@ -10,6 +10,9 @@ TARGETS = \
   threading/many-writers \
   threading/producer-consumer \
   threading/thread-join \
+  threading/sum-atomic \
+  threading/sum-mutex \
+  threading/sum-nosync \
   game-of-life/life \
   hello-library/hello \
 
@@ -37,6 +40,12 @@ threading/producer-consumer: threading/producer-consumer.scm
 	cyclone $^
 threading/thread-join      : threading/thread-join.scm
 	cyclone $^
+threading/sum-atomic   : threading/sum-atomic.scm
+	cyclone $^
+threading/sum-mutex    :  threading/sum-mutex.scm
+	cyclone $^
+threading/sum-nosync   : threading/sum-nosync.scm
+	cyclone $^
 game-of-life/life:
 	cd game-of-life ; make
 hello-library/hello:

examples/threading/sum-atomic.scm

@@ -1,4 +1,4 @@
-;;;; A simple example of using a condition variable to simulate thread-join
+;;;; Example of having multiple threads sum a variable using an atom.
 (import (scheme base)
         (scheme read)
         (scheme write)
@@ -18,7 +18,7 @@
       (sum-loop (- n 1))))
 
 (define (sum-entry-pt)
-  (sum-loop (* 10 100 100 100)))
+  (sum-loop (* 100 100 100)))
 
 ;; Thread - Do something, then let main thread know when we are done
 (define t1 (make-thread sum-entry-pt))
@@ -50,5 +50,5 @@
 (thread-join! t8)
 (thread-join! t9)
 (display "main thread done, sum = ")
-(display (ref *sum*))
+(display (deref *sum*))
 (newline)

examples/threading/sum-mutex.scm

@@ -1,4 +1,4 @@
-;;;; A simple example of using a condition variable to simulate thread-join
+;;;; Example of using a mutex to synchronize summing of a variable by multiple threads.
 (import (scheme base)
         (scheme read)
         (scheme write)
@@ -19,7 +19,7 @@
       (sum-loop (- n 1))))
 
 (define (sum-entry-pt)
-  (sum-loop (* 10 100 100 100)))
+  (sum-loop (* 100 100 100)))
 
 ;; Thread - Do something, then let main thread know when we are done
 (define t1 (make-thread sum-entry-pt))

examples/threading/sum-nosync.scm

@@ -1,12 +1,10 @@
-;;;; A simple example of using a condition variable to simulate thread-join
+;;;; Example of using multiple threads to sum a variable without synchronization.
+;;;; Returns inconsistent and wrong results due to a lack of thread coordination.
 (import (scheme base)
         (scheme read)
         (scheme write)
         (srfi 18))
 
-;(define cv (make-condition-variable))
-;(define m (make-mutex))
-
 (define *sum* 0)
 
 (define (sum-loop n)
@@ -16,7 +14,7 @@
       (sum-loop (- n 1))))
 
 (define (sum-entry-pt)
-  (sum-loop (* 10 100 100 100)))
+  (sum-loop (* 100 100 100)))
 
 ;; Thread - Do something, then let main thread know when we are done
 (define t1 (make-thread sum-entry-pt))