June 2018 Update

Task/Atomic-updates/Julia/atomic-updates.julia

@@ -0,0 +1,60 @@
+using StatsBase
+
+function runall()
+    nbuckets = 16
+    unfinish = true
+    spinner = ReentrantLock()
+    buckets = rand(1:99, nbuckets)
+    totaltrans = 0
+
+    bucketsum() = sum(buckets)
+    smallpause() = sleep(rand() / 2000)
+    picktwo() = (samplepair(nbuckets)...)
+    function equalizer()
+        while unfinish
+            smallpause()
+            if trylock(spinner)
+                i, j = picktwo()
+                sm = buckets[i] + buckets[j]
+                m = fld(sm + 1, 2)
+                buckets[i], buckets[j] = m, sm - m
+                totaltrans += 1
+                unlock(spinner)
+            end
+        end
+    end
+    function redistributor()
+        while unfinish
+            smallpause()
+            if trylock(spinner)
+                i, j = picktwo()
+                sm = buckets[i] + buckets[j]
+                buckets[i] = rand(0:sm)
+                buckets[j] = sm - buckets[i]
+                totaltrans += 1
+                unlock(spinner)
+            end
+        end
+    end
+    function accountant()
+        count = 0
+        while count < 16
+            smallpause()
+            if trylock(spinner)
+                println("Current state of buckets: $buckets. Total in buckets: $(bucketsum())")
+                unlock(spinner)
+                count += 1
+                sleep(1)
+            end
+        end
+        unfinish = false
+    end
+    t = time()
+    @async equalizer()
+    @async redistributor()
+    @async accountant()
+    while unfinish sleep(0.25) end
+    println("Total transactions: $totaltrans ($(round(Int, totaltrans / (time() - t))) unlocks per second).")
+end
+
+runall()