Testing Concurrent Software: Understanding Interleavings and Thread Scheduling, Exams of Programming Languages

Download Testing Concurrent Software: Understanding Interleavings and Thread Scheduling and more Exams Programming Languages in PDF only on Docsity! Testing concurrent software Testing concurrent software • Discussed in chapter 14 of JCP; read it • Will give some other ideas here Running multithreaded test cases • TestFramework.runOnce( MultithreadedTestCase test) – Creates and runs the threads once, under control of JVM thread scheduler • TestFramework. run200Interleavings( MultithreadedTestCase test) – Creates and runs the threads 200 times, generating different thread interleavings How do you get manual thread interleavings? • Specific -javaagent:lib/interleave.jar as a VM argument – Inserts calls to a special ThreadController.yield() method – Wraps calls to monitorenter, monitorexit, wait and notify – Doesn’t understand util.concurrent classes yet Which interleavings • An interleaving is when the system can decide when thread to allow to go next • Each thread has a number – Starting at 0 • Each interleaving is named – E.g., 0001110 • Thread 0 takes 3 steps, then thread 1 takes 3 steps, then thread 0 takes one step Options • -javaagent:lib/interleave.jar=trace – Print trace msgs at each context switch • -javaagent:lib/interleave.jar=prefix=cmsc433.p4 – Only instrument classes starting with cmsc433.p4 • In general, options are separated by commas, and have optional values • -javaagent:lib/interleave.jar=trace,prefix=cmsc433.p4 This is beta • This whole setup is beta • I’m sure that one or more of you will do something that breaks it • Each submission will be retested at least twice, if results aren’t consistent we will investigate it.