public void DegeneratingCommuteTest()
{
var a = new Shielded <int>();
int numInc = 100000;
int transactionCount = 0, commuteCount = 0;
ParallelEnumerable.Repeat(1, numInc / 2).ForAll(i => Shield.InTransaction(() => {
Interlocked.Increment(ref transactionCount);
a.Commute((ref int n) => {
Interlocked.Increment(ref commuteCount);
n++;
});
a.Commute((ref int n) => {
Interlocked.Increment(ref commuteCount);
n++;
});
// so, we cause it to degenerate. there was a subtle bug in enlisting which
// would allow a degenerated commute to execute before checking the lock!
int x = a;
}));
Assert.AreEqual(numInc, a);
// degenerated commutes conflict, which means transaction will repeat. conflict
// may be detected before the commute lambda actually gets to execute, so the
// trans count can be greater than commute count.
Assert.GreaterOrEqual(transactionCount, commuteCount / 2);
if (commuteCount == numInc)
{
Assert.Inconclusive();
}
}
public void SideEffectsInCommutes()
{
// due to running in an isolated context, side-effects from commutes get
// separately tracked, but must eventually execute just like any other
// SideEffect. this basically tests a part of TransactionItems.UnionWith().
var x = new Shielded <int>();
bool didItRun = false;
Thread t = null;
Shield.InTransaction(() =>
x.Commute((ref int _) => {
OneTimeConflict(ref t, x);
Shield.SideEffect(() => {
Assert.IsFalse(didItRun);
didItRun = true;
});
}));
Assert.IsTrue(didItRun);
didItRun = false;
t = null;
Shield.InTransaction(() =>
x.Commute((ref int _) => {
OneTimeConflict(ref t, x);
Shield.SyncSideEffect(() => {
Assert.IsFalse(didItRun);
didItRun = true;
});
}));
Assert.IsTrue(didItRun);
}
public void CommuteInACommute()
{
var a = new Shielded <int>();
var b = new Shielded <int>();
Assert.Throws <InvalidOperationException>(() =>
// there is only one _blockEnlist, and if it is "reused" by an inner call, it
// would get set to null when the inner commute ends. this would allow later code
// in the outer commute to violate the access restriction.
Shield.InTransaction(() =>
a.Commute((ref int aRef) => {
a.Commute((ref int aRef2) => aRef2++);
b.Value = 1;
})));
}
public void CommuteInACommute()
{
var a = new Shielded<int>();
var b = new Shielded<int>();
Assert.Throws<InvalidOperationException>(() =>
// there is only one _blockEnlist, and if it is "reused" by an inner call, it
// would get set to null when the inner commute ends. this would allow later code
// in the outer commute to violate the access restriction.
Shield.InTransaction(() =>
a.Commute((ref int aRef) => {
a.Commute((ref int aRef2) => aRef2++);
b.Value = 1;
})));
}
public void SyncSideEffectReadsCommute()
{
// in a SyncSideEffect you can read from a commuted field, but your ReadStamp has been set
// back to its original value, which is possibly lower than that field's last written
// value from some other, concurrent transaction. fields used to check for this, and roll back
// the transaction after it was already checked!
var a = new Shielded <int>();
int lastReadValue = 0;
Shield.InTransaction(() => {
a.Commute((ref int x) => x++);
var otherThread = new Thread(() => Shield.InTransaction(() =>
{
a.Value = 10;
}));
otherThread.Start();
otherThread.Join();
Shield.SideEffect(null, () => Assert.Fail("Invalid rollback occurred."));
Shield.SyncSideEffect(() =>
{
// here, the field's last written value has version 1, and our ReadStamp is 0.
// however, the commute subtransaction had ReadStamp 1, and it checked out, so,
// this should not be a problem.
lastReadValue = a.Value;
});
});
Assert.AreEqual(11, lastReadValue);
}
public void EventTest()
{
var a = new Shielded <int>(1);
var eventCount = new Shielded <int>();
EventHandler <EventArgs> ev =
(sender, arg) => eventCount.Commute((ref int e) => e++);
Assert.Throws <InvalidOperationException>(() =>
a.Changed.Subscribe(ev));
Shield.InTransaction(() =>
{
a.Changed.Subscribe(ev);
var t = new Thread(() =>
Shield.InTransaction(() =>
a.Modify((ref int x) => x++)));
t.Start();
t.Join();
var t2 = new Thread(() =>
Shield.InTransaction(() =>
a.Modify((ref int x) => x++)));
t2.Start();
t2.Join();
});
Assert.AreEqual(0, eventCount);
Shield.InTransaction(() => {
a.Modify((ref int x) => x++);
});
Assert.AreEqual(1, eventCount);
Thread tUnsub = null;
Shield.InTransaction(() => {
a.Changed.Unsubscribe(ev);
a.Modify((ref int x) => x++);
if (tUnsub == null)
{
tUnsub = new Thread(() =>
{
Shield.InTransaction(() => {
a.Modify((ref int x) => x++);
a.Modify((ref int x) => x++);
});
});
tUnsub.Start();
tUnsub.Join();
}
});
// the other thread must still see the subscription...
Assert.AreEqual(3, eventCount);
Shield.InTransaction(() => a.Modify((ref int x) => x++));
Assert.AreEqual(3, eventCount);
}
public void PreCommitFirstCommute()
{
var a = new Shielded <int>();
var b = new Shielded <int>();
using (Shield.PreCommit(() => a == 0 || true, () => b.Commute((ref int n) => n++)))
Shield.InTransaction(() => a.Value = 1);
Assert.AreEqual(1, a);
Assert.AreEqual(1, b);
}
public void CommuteInvariantProblem()
{
// since pre-commits have no limitations on access, they cannot safely
// execute within the commute sub-transaction. if they would, then this
// test would fail on the last assertion. instead, pre-commits cause commutes
// to degenerate.
var testField = new Shielded <int>();
var effectField = new Shielded <int>();
var failCommitCount = new Shielded <int>();
var failVisibleCount = 0;
// check if the effect field was written to, that the testField is even.
Shield.PreCommit(() => effectField > 0, () => {
if ((testField & 1) == 1)
{
Interlocked.Increment(ref failVisibleCount);
// this will always fail to commit, confirming that the transaction
// is already bound to fail. but, the failVisibleCount might be >0.
failCommitCount.Modify((ref int n) => n++);
}
});
var thread = new Thread(() => {
// if the testField is even, increment the effectField commutatively.
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
if ((testField & 1) == 0)
{
effectField.Commute((ref int n) => n++);
}
});
}
});
thread.Start();
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
testField.Modify((ref int n) => n++);
});
}
thread.Join();
Assert.AreEqual(0, failCommitCount);
Assert.AreEqual(0, failVisibleCount);
}
public void CommuteInvariantProblem()
{
// since pre-commits have no limitations on access, they cannot safely
// execute within the commute sub-transaction. if they would, then this
// test would fail on the last assertion. instead, pre-commits cause commutes
// to degenerate.
var testField = new Shielded<int>();
var effectField = new Shielded<int>();
var failCommitCount = new Shielded<int>();
var failVisibleCount = 0;
// check if the effect field was written to, that the testField is even.
Shield.PreCommit(() => effectField > 0, () => {
if ((testField & 1) == 1)
{
Interlocked.Increment(ref failVisibleCount);
// this will always fail to commit, confirming that the transaction
// is already bound to fail. but, the failVisibleCount will be >0.
failCommitCount.Modify((ref int n) => n++);
}
});
var thread = new Thread(() => {
// if the testField is even, increment the effectField commutatively.
foreach (int i in Enumerable.Range(1, 1000))
Shield.InTransaction(() => {
if ((testField & 1) == 0)
{
effectField.Commute((ref int n) => n++);
}
});
});
thread.Start();
foreach (int i in Enumerable.Range(1, 1000))
Shield.InTransaction(() => {
testField.Modify((ref int n) => n++);
});
thread.Join();
Assert.AreEqual(0, failCommitCount);
Assert.AreEqual(0, failVisibleCount);
}
public void BasicCommuteTest()
{
var a = new Shielded <int>();
Shield.InTransaction(() => a.Commute((ref int n) => n++));
Assert.AreEqual(1, a);
Shield.InTransaction(() =>
{
Assert.AreEqual(1, a);
a.Commute((ref int n) => n++);
Assert.AreEqual(2, a);
});
Assert.AreEqual(2, a);
Shield.InTransaction(() =>
{
a.Commute((ref int n) => n++);
Assert.AreEqual(3, a);
});
Assert.AreEqual(3, a);
int transactionCount = 0, commuteCount = 0;
ParallelEnumerable.Repeat(1, 100).ForAll(i => Shield.InTransaction(() => {
Interlocked.Increment(ref transactionCount);
a.Commute((ref int n) => {
Interlocked.Increment(ref commuteCount);
Thread.Sleep(10); // needs this.. (running on Mono 2.10)
n++;
});
}));
Assert.AreEqual(103, a);
// commutes never conflict (!)
Assert.AreEqual(100, transactionCount);
Assert.Greater(commuteCount, 100);
Shield.InTransaction(() => {
a.Commute((ref int n) => n -= 3);
a.Commute((ref int n) => n--);
});
Assert.AreEqual(99, a);
}
public void CommuteTest()
{
var a = new Shielded<int>();
Shield.InTransaction(() => a.Commute((ref int n) => n++));
Assert.AreEqual(1, a);
Shield.InTransaction(() =>
{
Assert.AreEqual(1, a);
a.Commute((ref int n) => n++);
Assert.AreEqual(2, a);
});
Assert.AreEqual(2, a);
Shield.InTransaction(() =>
{
a.Commute((ref int n) => n++);
Assert.AreEqual(3, a);
});
Assert.AreEqual(3, a);
int transactionCount = 0, commuteCount = 0;
ParallelEnumerable.Repeat(1, 100).ForAll(i => Shield.InTransaction(() => {
Interlocked.Increment(ref transactionCount);
a.Commute((ref int n) => {
Interlocked.Increment(ref commuteCount);
Thread.Sleep(10); // needs this.. (running on Mono 2.10)
n++;
});
}));
Assert.AreEqual(103, a);
// commutes never conflict (!)
Assert.AreEqual(100, transactionCount);
Assert.Greater(commuteCount, 100);
Shield.InTransaction(() => {
a.Commute((ref int n) => n -= 3);
a.Commute((ref int n) => n--);
});
Assert.AreEqual(99, a);
}
static void SimpleOps()
{
long time;
_timer = Stopwatch.StartNew();
var numItems = 1000000;
var repeatsPerTrans = 50;
Console.WriteLine(
"Testing simple ops with {0} iterations, and repeats per trans (N) = {1}",
numItems, repeatsPerTrans);
var accessTest = new Shielded<int>();
Timed("WARM UP", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
accessTest.Value = 3;
var a = accessTest.Value;
accessTest.Modify((ref int n) => n = 5);
a = accessTest.Value;
});
});
var emptyTime = Timed("empty transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => { });
});
var emptyReturningTime = Timed("1 empty transaction w/ result", numItems, () => {
// this version uses the generic, result-returning InTransaction, which involves creation
// of a closure, i.e. an allocation.
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => 5);
});
var outOfTrReadTime = Timed("N out-of-tr. reads", numItems, () => {
// this version uses the generic, result-returning InTransaction, which involves creation
// of a closure, i.e. an allocation.
foreach (var k in Enumerable.Repeat(1, numItems * repeatsPerTrans))
{
var a = accessTest.Value;
}
});
// the purpose here is to get a better picture of the expense of using Shielded. a more
// complex project would probably, during one transaction, repeatedly access the same
// field. does this cost much more than a single-access transaction? if it is the same
// field, then any significant extra expense is unacceptable.
var oneReadTime = Timed("1-read transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
var a = accessTest.Value;
});
});
var nReadTime = Timed("N-reads transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
int a;
for (int i = 0; i < repeatsPerTrans; i++)
a = accessTest.Value;
});
});
var oneReadModifyTime = Timed("1-read-1-modify tr.", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
var a = accessTest.Value;
accessTest.Modify((ref int n) => n = 1);
});
});
// Assign is no longer commutable, for performance reasons. It is faster,
// particularly when repeated (almost 10 times), and you can see the difference
// that not reading the old value does.
var oneReadAssignTime = Timed("1-read-1-assign tr.", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
var a = accessTest.Value;
accessTest.Value = 1;
});
});
var oneModifyTime = Timed("1-modify transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => accessTest.Modify((ref int n) => n = 1));
});
var nModifyTime = Timed("N-modify transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
for (int i = 0; i < repeatsPerTrans; i++)
accessTest.Modify((ref int n) => n = 1);
});
});
var accessTest2 = new Shielded<int>();
var modifyModifyTime = Timed("modify-modify transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
accessTest.Modify((ref int n) => n = 1);
accessTest2.Modify((ref int n) => n = 2);
});
});
// here Modify is the first call, making all Reads as fast as can be,
// reading direct from local storage.
var oneModifyNReadTime = Timed("1-modify-N-reads tr.", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
accessTest.Modify((ref int n) => n = 1);
int a;
for (int i = 0; i < repeatsPerTrans; i++)
a = accessTest.Value;
});
});
var oneAssignTime = Timed("1-assign transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => accessTest.Value = 1);
});
var nAssignTime = Timed("N-assigns transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => {
for (int i = 0; i < repeatsPerTrans; i++)
accessTest.Value = 1;
});
});
var oneCommuteTime = Timed("1-commute transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => accessTest.Commute((ref int n) => n = 1));
});
var nCommuteTime = Timed("N-commute transactions", numItems, () => {
foreach (var k in Enumerable.Repeat(1, numItems/10))
Shield.InTransaction(() => {
for (int i = 0; i < repeatsPerTrans; i++)
accessTest.Commute((ref int n) => n = 1);
});
});
Console.WriteLine("\ncost of empty transaction = {0:0.000} us", emptyTime / (numItems / 1000.0));
Console.WriteLine("cost of the closure in InTransaction<T> = {0:0.000} us",
(emptyReturningTime - emptyTime) / (numItems / 1000.0));
Console.WriteLine("cost of an out-of-tr. read = {0:0.000} us",
outOfTrReadTime * 1000.0 / (numItems * repeatsPerTrans));
Console.WriteLine("cost of the first read = {0:0.000} us",
(oneReadTime - emptyTime) / (numItems / 1000.0));
Console.WriteLine("cost of an additional read = {0:0.000} us",
(nReadTime - oneReadTime) / ((repeatsPerTrans - 1) * numItems / 1000.0));
Console.WriteLine("cost of Modify after read = {0:0.000} us",
(oneReadModifyTime - oneReadTime) / (numItems / 1000.0));
Console.WriteLine("cost of Assign after read = {0:0.000} us",
(oneReadAssignTime - oneReadTime) / (numItems / 1000.0));
Console.WriteLine("cost of the first Modify = {0:0.000} us",
(oneModifyTime - emptyTime) / (numItems / 1000.0));
Console.WriteLine("cost of an additional Modify = {0:0.000} us",
(nModifyTime - oneModifyTime) / ((repeatsPerTrans - 1) * numItems / 1000.0));
Console.WriteLine("cost of a second, different Modify = {0:0.000} us",
(modifyModifyTime - oneModifyTime) / (numItems / 1000.0));
Console.WriteLine("cost of a read after Modify = {0:0.000} us",
(oneModifyNReadTime - oneModifyTime) / (repeatsPerTrans * numItems / 1000.0));
Console.WriteLine("cost of the first Assign = {0:0.000} us",
(oneAssignTime - emptyTime) / (numItems / 1000.0));
Console.WriteLine("cost of an additional Assign = {0:0.000} us",
(nAssignTime - oneAssignTime) / ((repeatsPerTrans - 1) * numItems / 1000.0));
Console.WriteLine("cost of the first commute = {0:0.000} us",
(oneCommuteTime - emptyTime) / (numItems / 1000.0));
Console.WriteLine("cost of an additional commute = {0:0.000} us",
(nCommuteTime*10 - oneCommuteTime) / ((repeatsPerTrans - 1) * numItems / 1000.0));
}
public void ComplexCommute()
{
// some more complex commute combinations. first, with ShieldedSeq ops.
var seq = new ShieldedSeq <int>();
// just a test for proper commute ordering
Shield.InTransaction(() => {
seq.Append(1);
seq.Append(2);
seq.Append(3);
seq.Remove(2);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq.Count);
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(3, seq[1]);
});
// a test for commutability of Append()
Shield.InTransaction(() => { seq.Clear(); });
int transactionCount = 0;
Thread oneTimer = null;
Shield.InTransaction(() => {
transactionCount++;
seq.Append(1);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(2);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(1, transactionCount);
Assert.AreEqual(2, seq.Count);
// the "subthread" commited the append first, so:
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(1, seq[1]);
Assert.IsTrue(seq.Any());
// test for a commute degeneration - reading the head of a list causes
// appends done in the same transaction to stop being commutable. for
// simplicity - you could continue from the head on to the tail, and it cannot
// thus be a commute, you read it. it could, of course, be done that it still
// is a commute, but that would make it pretty complicated.
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
seq.Append(4);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(3, seq.Count);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
Assert.AreEqual(4, seq[2]);
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
// if we switch the order, doesn't matter.
transactionCount++;
seq.Append(4);
Assert.AreEqual(1, seq.TakeHead());
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(3, seq.Count);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
Assert.AreEqual(4, seq[2]);
// here the removal takes out the last element in the list. this absolutely cannot
// commute, because it read from the only element's Next field, and the Seq
// knew that it was the last element. it must conflict.
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); });
Assert.AreEqual(1, seq[0]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
seq.Append(3);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(2);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(2, seq.Count);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
// it is not allowed to read another Shielded from a Shielded.Commute()!
// this greatly simplifies things. if you still want to use a value from another
// Shielded, you must read it in main trans, forcing it's commutes to degenerate.
var a = new Shielded <int>();
var b = new Shielded <int>();
Assert.Throws <InvalidOperationException>(() =>
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => n = a);
}));
Assert.Throws <InvalidOperationException>(() =>
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => {
n = 1;
a.Commute((ref int n2) => n2 = 2);
});
}));
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => n = a);
Assert.Throws <InvalidOperationException>(() => {
var x = b.Value;
});
});
}
public void DegeneratingCommuteTest()
{
var a = new Shielded<int>();
int numInc = 100000;
int transactionCount = 0, commuteCount = 0;
ParallelEnumerable.Repeat(1, numInc/2).ForAll(i => Shield.InTransaction(() => {
Interlocked.Increment(ref transactionCount);
a.Commute((ref int n) => {
Interlocked.Increment(ref commuteCount);
n++;
});
a.Commute((ref int n) => {
Interlocked.Increment(ref commuteCount);
n++;
});
// so, we cause it to degenerate. there was a subtle bug in enlisting which
// would allow a degenerated commute to execute before checking the lock!
int x = a;
}));
Assert.AreEqual(numInc, a);
// degenerated commutes conflict, which means transaction will repeat. conflict
// may be detected before the commute lambda actually gets to execute, so the
// trans count can be greater than commute count.
Assert.GreaterOrEqual(transactionCount, commuteCount/2);
// classic, just to confirm there was at least one conflict.
Assert.Greater(commuteCount, numInc);
}
public static void SimpleCommuteTest()
{
var a = new Shielded<int>();
Shield.InTransaction(() => a.Commute((ref int n) => n++));
Console.WriteLine(a);
Shield.InTransaction(() =>
{
Console.WriteLine(a);
a.Commute((ref int n) => n++);
Console.WriteLine(a);
});
Console.WriteLine(a);
Shield.InTransaction(() =>
{
a.Commute((ref int n) => n++);
Console.WriteLine(a);
});
Console.WriteLine(a);
}
public void ComplexCommute()
{
// some more complex commute combinations. first, with ShieldedSeq ops.
var seq = new ShieldedSeq<int>();
Shield.InTransaction(() => {
// test for potential disorder of the seq commutes.
seq.Append(1);
seq.Clear();
Assert.IsFalse(seq.HasAny);
Assert.AreEqual(0, seq.Count);
});
Shield.InTransaction(() => {
seq.Append(1);
seq.Append(2);
seq.Append(3);
seq.Remove(2);
Assert.IsTrue(seq.HasAny);
Assert.AreEqual(2, seq.Count);
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(3, seq[1]);
seq.Clear();
Assert.IsFalse(seq.HasAny);
Assert.AreEqual(0, seq.Count);
});
Shield.InTransaction(() => { seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
int transactionCount = 0;
Thread oneTimer = null;
Shield.InTransaction(() => {
// here's a weird one - the seq is only partially commuted, due to reading
// from the head, but it still commutes with a trans that is only appending.
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
// Count or tail were not read! Clearing can commute with appending.
seq.Clear();
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(1, transactionCount);
Assert.AreEqual(0, seq.Count);
Assert.IsFalse(seq.HasAny);
Shield.InTransaction(() => { seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
// same as above, but with appending, does not work. reading the _head screws it up,
// because you could continue from the head to the last item.
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
seq.Append(4);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(3, seq.Count);
Assert.IsTrue(seq.HasAny);
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
Assert.AreEqual(4, seq[2]);
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
// if we switch the order, doesn't matter.
transactionCount++;
seq.Append(4);
Assert.AreEqual(1, seq.TakeHead());
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(3, seq.Count);
Assert.IsTrue(seq.HasAny);
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
Assert.AreEqual(4, seq[2]);
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); });
Assert.AreEqual(1, seq[0]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
// here the removal takes out the last element in the list. this cannot
// commute, because it read from the only element's Next field, and the Seq
// knew that it was the last element. it must conflict.
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
seq.Append(3);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(2);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(2, seq.Count);
Assert.IsTrue(seq.HasAny);
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
// it is not allowed to read another Shielded from a Shielded.Commute()!
// this greatly simplifies things. if you still want to use a value from another
// Shielded, you must read it in main trans, forcing it's commutes to degenerate.
var a = new Shielded<int>();
var b = new Shielded<int>();
try
{
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => n = a);
});
Assert.Fail();
}
catch (InvalidOperationException) {}
try
{
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => { n = 1; a.Commute((ref int n2) => n2 = 2); });
});
Assert.Fail();
}
catch (InvalidOperationException) {}
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => n = a);
try
{
var x = b.Read;
Assert.Fail();
}
catch (InvalidOperationException) {}
});
}
public void EventTest()
{
var a = new Shielded<int>(1);
var eventCount = new Shielded<int>();
EventHandler<EventArgs> ev =
(sender, arg) => eventCount.Commute((ref int e) => e++);
try
{
a.Changed.Subscribe(ev);
Assert.Fail();
}
catch (InvalidOperationException) {}
Shield.InTransaction(() =>
{
a.Changed.Subscribe(ev);
var t = new Thread(() =>
{
Shield.InTransaction(() => {
a.Modify((ref int x) => x++);
});
});
t.Start();
t.Join();
var t2 = new Thread(() =>
{
Shield.InTransaction(() => {
a.Modify((ref int x) => x++);
});
});
t2.Start();
t2.Join();
});
Assert.AreEqual(0, eventCount);
Shield.InTransaction(() => {
a.Modify((ref int x) => x++);
});
Assert.AreEqual(1, eventCount);
Thread tUnsub = null;
Shield.InTransaction(() => {
a.Changed.Unsubscribe(ev);
a.Modify((ref int x) => x++);
if (tUnsub == null)
{
tUnsub = new Thread(() =>
{
Shield.InTransaction(() => {
a.Modify((ref int x) => x++);
a.Modify((ref int x) => x++);
});
});
tUnsub.Start();
tUnsub.Join();
}
});
// the other thread must still see the subscription...
Assert.AreEqual(3, eventCount);
Shield.InTransaction(() => a.Modify((ref int x) => x++));
Assert.AreEqual(3, eventCount);
}
public static void BetShopPoolTest()
{
int numThreads = 3;
int numTickets = 200000;
int numEvents = 100;
var barrier = new Barrier(2);
var betShop = new BetShop(numEvents);
var randomizr = new Random();
var bags = new List<Action>[numThreads];
var threads = new Thread[numThreads];
for (int i = 0; i < numThreads; i++)
{
var bag = bags[i] = new List<Action>();
threads[i] = new Thread(() => {
foreach (var a in bag)
a();
});
}
var complete = new Shielded<int>();
IDisposable completeCond = null;
completeCond = Shield.Conditional(() => complete == numTickets, () => {
barrier.SignalAndWait();
completeCond.Dispose();
});
var reportEvery = 10000;
Shielded<int> lastReport = new Shielded<int>(0);
Shielded<DateTime> lastTime = new Shielded<DateTime>(DateTime.UtcNow);
using (Shield.Conditional(
() => betShop.Tickets.Count >= lastReport + reportEvery,
() => {
DateTime newNow = DateTime.UtcNow;
int count = betShop.Tickets.Count;
int speed = (count - lastReport) * 1000 / (int)newNow.Subtract(lastTime).TotalMilliseconds;
lastTime.Value = newNow;
lastReport.Modify((ref int n) => n += reportEvery);
Shield.SideEffect(() =>
Console.Write("\n{0} at {1} item/s", count, speed));
}))
{
foreach (var i in Enumerable.Range(0, numTickets))
{
decimal payIn = (randomizr.Next(10) + 1m) * 1;
int event1Id = randomizr.Next(numEvents) + 1;
int event2Id = randomizr.Next(numEvents) + 1;
int event3Id = randomizr.Next(numEvents) + 1;
int offer1Ind = randomizr.Next(3);
int offer2Ind = randomizr.Next(3);
int offer3Ind = randomizr.Next(3);
bags[i % numThreads].Add(() => Shield.InTransaction(() => {
var offer1 = betShop.Events[event1Id].BetOffers[offer1Ind];
var offer2 = betShop.Events[event2Id].BetOffers[offer2Ind];
var offer3 = betShop.Events[event3Id].BetOffers[offer3Ind];
betShop.BuyTicket(payIn, offer1, offer2, offer3);
complete.Commute((ref int n) => n++);
}));
}
_timer = Stopwatch.StartNew();
for (int i = 0; i < numThreads; i++)
threads[i].Start();
barrier.SignalAndWait();
}
var time = _timer.ElapsedMilliseconds;
var totalCorrect = betShop.VerifyTickets();
Console.WriteLine(" {0} ms with {1} tickets paid in and is {2}.",
time, betShop.Tickets.Count, totalCorrect ? "correct" : "incorrect");
}
public void ComplexCommute()
{
// some more complex commute combinations. first, with ShieldedSeq ops.
var seq = new ShieldedSeq<int>();
// just a test for proper commute ordering
Shield.InTransaction(() => {
seq.Append(1);
seq.Append(2);
seq.Append(3);
seq.Remove(2);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq.Count);
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(3, seq[1]);
});
// a test for commutability of Append()
Shield.InTransaction(() => { seq.Clear(); });
int transactionCount = 0;
Thread oneTimer = null;
Shield.InTransaction(() => {
transactionCount++;
seq.Append(1);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(2);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(1, transactionCount);
Assert.AreEqual(2, seq.Count);
// the "subthread" commited the append first, so:
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(1, seq[1]);
Assert.IsTrue(seq.Any());
// test for a commute degeneration - reading the head of a list causes
// appends done in the same transaction to stop being commutable. for
// simplicity - you could continue from the head on to the tail, and it cannot
// thus be a commute, you read it. it could, of course, be done that it still
// is a commute, but that would make it pretty complicated.
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
seq.Append(4);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(3, seq.Count);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
Assert.AreEqual(4, seq[2]);
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); seq.Append(2); });
Assert.AreEqual(1, seq[0]);
Assert.AreEqual(2, seq[1]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
// if we switch the order, doesn't matter.
transactionCount++;
seq.Append(4);
Assert.AreEqual(1, seq.TakeHead());
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(3);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(3, seq.Count);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
Assert.AreEqual(4, seq[2]);
// here the removal takes out the last element in the list. this absolutely cannot
// commute, because it read from the only element's Next field, and the Seq
// knew that it was the last element. it must conflict.
Shield.InTransaction(() => { seq.Clear(); seq.Append(1); });
Assert.AreEqual(1, seq[0]);
transactionCount = 0;
oneTimer = null;
Shield.InTransaction(() => {
transactionCount++;
Assert.AreEqual(1, seq.TakeHead());
seq.Append(3);
if (oneTimer == null)
{
oneTimer = new Thread(() => Shield.InTransaction(() =>
{
seq.Append(2);
}));
oneTimer.Start();
oneTimer.Join();
}
});
Assert.AreEqual(2, transactionCount);
Assert.AreEqual(2, seq.Count);
Assert.IsTrue(seq.Any());
Assert.AreEqual(2, seq[0]);
Assert.AreEqual(3, seq[1]);
// it is not allowed to read another Shielded from a Shielded.Commute()!
// this greatly simplifies things. if you still want to use a value from another
// Shielded, you must read it in main trans, forcing it's commutes to degenerate.
var a = new Shielded<int>();
var b = new Shielded<int>();
Assert.Throws<InvalidOperationException>(() =>
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => n = a);
}));
Assert.Throws<InvalidOperationException>(() =>
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => {
n = 1;
a.Commute((ref int n2) => n2 = 2);
});
}));
Shield.InTransaction(() => {
a.Commute((ref int n) => n = 1);
b.Commute((ref int n) => n = a);
Assert.Throws<InvalidOperationException>(() => {
var x = b.Value;
});
});
}
