September Morn Update

Task/Checkpoint-synchronization/Julia/checkpoint-synchronization.julia

@@ -0,0 +1,20 @@
+function runsim(numworkers, runs)
+    for count in 1:runs
+        @sync begin
+            for worker in 1:numworkers
+                @async begin
+                    tasktime = rand()
+                    sleep(tasktime)
+                    println("Worker $worker finished after $tasktime seconds")
+                end
+            end
+        end
+        println("Checkpoint reached for run $count.")
+    end
+    println("Finished all runs.\n")
+end
+
+const trials = [[3, 2], [4, 1], [2, 5], [7, 6]]
+for trial in trials
+    runsim(trial[1], trial[2])
+end

Task/Checkpoint-synchronization/Perl-6/checkpoint-synchronization.pl6

@@ -0,0 +1,41 @@
+#!/usr/bin/env perl6
+
+use v6;
+
+my $TotalWorkers = 3;
+my $BatchToRun = 3;
+my @TimeTaken = (5..15); # in seconds
+
+my $batch_progress = 0;
+my @batch_lock = map { Semaphore.new(1) } , ^$TotalWorkers;
+my $lock = Lock.new;
+
+sub assembly_line ($ID) {
+   my $wait;
+   for ^$BatchToRun -> $j {
+      $wait = @TimeTaken.roll;
+      say "Worker ",$ID," at batch $j will work for ",$wait," seconds ..";
+      sleep($wait);
+      $lock.protect: {
+         my $k = ++$batch_progress;
+         print "Worker ",$ID," is done and update batch $j complete counter ";
+         say "to $k of $TotalWorkers";
+         if ($batch_progress == $TotalWorkers) {
+            say ">>>>> batch $j completed.";
+            $batch_progress = 0; # reset for next batch
+            for @batch_lock { .release }; # and ready for next batch
+         };
+       };
+
+       @batch_lock[$ID].acquire; # for next batch
+   }
+}
+
+for ^$TotalWorkers -> $i {
+   Thread.start(
+      sub {
+         @batch_lock[$i].acquire;
+         assembly_line($i);
+      }
+   );
+}

Task/Checkpoint-synchronization/Phix/checkpoint-synchronization.phix

@@ -0,0 +1,50 @@
+-- demo\rosetta\checkpoint_synchronisation.exw
+constant NPARTS = 3
+integer workers = 0
+sequence waiters = {}
+bool terminate = false
+
+procedure checkpoint(integer task_id)
+    if length(waiters)+1=NPARTS or terminate then
+        printf(1,"checkpoint\n")
+        for i=1 to length(waiters) do
+            task_schedule(waiters[i],1)
+        end for
+        waiters = {}
+    else
+        waiters &= task_id
+        task_suspend(task_id)
+        task_yield()
+    end if
+end procedure
+
+procedure worker(string name)
+    printf(1,"worker %s running\n",{name})
+    while not terminate do
+        printf(1,"worker %s begins part\n",{name})
+        task_delay(rnd())
+        printf(1,"worker %s completes part\n",{name})
+        checkpoint(task_self())
+        if rnd()>0.95 then exit end if
+        task_delay(rnd())
+    end while
+    printf(1,"worker %s leaves\n",{name})
+    workers -= 1
+end procedure
+
+string name = "A"
+
+while get_key()!=#1B do -- (key escape to shut down)
+    if workers<NPARTS then
+        integer task_id = task_create(routine_id("worker"),{name})
+        task_schedule(task_id,1)
+        name[1] += 1
+        workers += 1
+    end if
+    task_yield()
+end while
+printf(1,"escape keyed\n")
+terminate = true
+while workers>0 do
+    task_yield()
+end while

Task/Checkpoint-synchronization/Python/checkpoint-synchronization.py

@@ -0,0 +1,33 @@
+"""
+
+Based on https://pymotw.com/3/threading/
+
+"""
+
+import threading
+import time
+import random
+
+
+def worker(workernum, barrier):
+    # task 1
+    sleeptime = random.random()
+    print('Starting worker '+str(workernum)+" task 1, sleeptime="+str(sleeptime))
+    time.sleep(sleeptime)
+    print('Exiting worker'+str(workernum))
+    barrier.wait()
+    # task 2
+    sleeptime = random.random()
+    print('Starting worker '+str(workernum)+" task 2, sleeptime="+str(sleeptime))
+    time.sleep(sleeptime)
+    print('Exiting worker'+str(workernum))
+
+barrier = threading.Barrier(3)
+
+w1 = threading.Thread(target=worker, args=((1,barrier)))
+w2 = threading.Thread(target=worker, args=((2,barrier)))
+w3 = threading.Thread(target=worker, args=((3,barrier)))
+
+w1.start()
+w2.start()
+w3.start()