public SimulatedFlakyDevice(IDevice underlying, ErrorSimulationOptions options) : base(underlying.FileName, underlying.SectorSize, underlying.Capacity)
{
this.underlying = underlying;
this.options = options;
permanentlyFailedRangesStart = new List <long>();
permanentlyFailedRangesEnd = new List <long>();
versionScheme = new SimpleVersionScheme();
random = new ThreadLocal <Random>(() => new Random());
}
public void LargeConcurrentTest()
{
var tested = new SimpleVersionScheme();
var protectedVal = 1L;
var termination = new ManualResetEventSlim();
var workerThreads = new List <Thread>();
int numThreads = Math.Min(8, Environment.ProcessorCount / 2);
// Force lots of interleavings by having many threads
for (var i = 0; i < numThreads; i++)
{
var t = new Thread(() =>
{
while (!termination.IsSet)
{
var v = tested.Enter();
Assert.AreEqual(v, Interlocked.Read(ref protectedVal));
tested.Leave();
}
});
workerThreads.Add(t);
t.Start();
}
for (var i = 0; i < 1000; i++)
{
tested.TryAdvanceVersion((vOld, vNew) =>
{
Assert.AreEqual(vOld, Interlocked.Read(ref protectedVal));
// Flip sign to simulate critical section processing
protectedVal = -vOld;
Thread.Yield();
protectedVal = vNew;
});
}
termination.Set();
foreach (var t in workerThreads)
{
t.Join();
}
}
public void SimpleTest()
{
var tested = new SimpleVersionScheme();
var protectedVal = 0;
var v = tested.Enter();
Assert.AreEqual(1, v);
tested.TryAdvanceVersion((_, _) => protectedVal = 1);
Thread.Sleep(10);
// because of ongoing protection, nothing should happen yet
tested.Leave();
// As soon as protection is dropped, action should be done.
Assert.AreEqual(1, protectedVal);
// Next thread sees new version
v = tested.Enter();
Assert.AreEqual(v, 2);
tested.Leave();
}
public void SingleThreadTest()
{
var tested = new SimpleVersionScheme();
var protectedVal = 0;
var v = tested.Enter();
Assert.AreEqual(1, v);
tested.Leave();
tested.TryAdvanceVersion((_, _) => protectedVal = 1);
Assert.AreEqual(1, protectedVal);
tested.TryAdvanceVersion((_, _) => protectedVal = 2, 4);
Assert.AreEqual(2, protectedVal);
v = tested.Enter();
Assert.AreEqual(4, v);
tested.Leave();
}
