private void CountTracking()
{
int reportEvery = 10000;
Shielded<int> lastReport = new Shielded<int>(0);
Shielded<DateTime> lastTime = new Shielded<DateTime>(DateTime.UtcNow);
Shield.Conditional(() => _processed >= lastReport + reportEvery, () =>
{
DateTime newNow = DateTime.UtcNow;
int count = _processed;
int speed = (count - lastReport) * 1000 / (int)newNow.Subtract(lastTime).TotalMilliseconds;
lastTime.Assign(newNow);
lastReport.Modify((ref int n) => n += reportEvery);
int sc = _subscribeCount;
int ptc = _processTestCount;
int pbc = _processBodyCount;
Shield.SideEffect(() =>
{
Console.WriteLine(
"{0} at {1} item/s, stats ( {2}, {3}, {4} )",
count, speed, sc, ptc, pbc);
});
return true;
});
}
public void ConditionalTest()
{
var x = new Shielded<int>();
var testCounter = 0;
var triggerCommits = 0;
Shield.Conditional(() => {
Interlocked.Increment(ref testCounter);
return x > 0 && (x & 1) == 0;
},
() => {
Shield.SideEffect(() =>
Interlocked.Increment(ref triggerCommits));
Assert.IsTrue(x > 0 && (x & 1) == 0);
});
const int count = 1000;
ParallelEnumerable.Repeat(1, count).ForAll(i =>
Shield.InTransaction(() => x.Modify((ref int n) => n++)));
// one more, for the first call to Conditional()! btw, if this conditional were to
// write anywhere, he might conflict, and an interlocked counter would give more due to
// repetitions. so, this confirms reader progress too.
Assert.AreEqual(count + 1, testCounter);
// every change triggers it, but by the time it starts, another transaction might have
// committed, so this is not a fixed number.
Assert.Greater(triggerCommits, 0);
// a conditional which does not depend on any Shielded is not allowed!
int a = 5;
Assert.Throws<InvalidOperationException>(() =>
Shield.Conditional(() => a > 10, () => { }));
bool firstTime = true;
var x2 = new Shielded<int>();
// this one succeeds in registering, but fails as soon as it gets triggered, due to changing it's
// test's access pattern to an empty set.
Shield.Conditional(() => {
if (firstTime)
{
firstTime = false;
return x2 == 0;
}
else
// this is of course invalid, and when reaching here we have not touched any Shielded obj.
return true;
}, () => { });
try
{
// this will trigger the conditional
Shield.InTransaction(() => x2.Modify((ref int n) => n++));
Assert.Fail();
}
catch (AggregateException aggr)
{
Assert.AreEqual(1, aggr.InnerExceptions.Count);
Assert.AreEqual(typeof(InvalidOperationException), aggr.InnerException.GetType());
}
}
public void SkewWriteTest()
{
var cats = new Shielded <int>(1);
var dogs = new Shielded <int>(1);
int transactionCount = 0;
Task.WaitAll(
Enumerable.Range(1, 2).Select(i => Task.Factory.StartNew(() =>
Shield.InTransaction(() =>
{
Interlocked.Increment(ref transactionCount);
if (cats + dogs < 3)
{
Thread.Sleep(200);
if (i == 1)
{
cats.Modify((ref int n) => n++);
}
else
{
dogs.Modify((ref int n) => n++);
}
}
}), TaskCreationOptions.LongRunning)).ToArray());
Assert.AreEqual(3, cats + dogs);
Assert.AreEqual(3, transactionCount);
}
public void SideEffectTest()
{
var x = new Shielded <DateTime>(DateTime.UtcNow);
try
{
Shield.InTransaction(() =>
{
Shield.SideEffect(() => {
Assert.Fail("Suicide transaction has committed.");
},
() => {
throw new IgnoreMe();
});
// in case Assign() becomes commutative, we use Modify() to ensure conflict.
x.Modify((ref DateTime d) => d = DateTime.UtcNow);
var t = new Thread(() =>
Shield.InTransaction(() =>
x.Modify((ref DateTime d) => d = DateTime.UtcNow)));
t.Start();
t.Join();
});
Assert.Fail("Suicide transaction did not throw.");
}
catch (AggregateException aggr)
{
Assert.AreEqual(1, aggr.InnerExceptions.Count);
Assert.AreEqual(typeof(IgnoreMe), aggr.InnerException.GetType());
}
bool commitFx = false;
Shield.InTransaction(() => {
Shield.SideEffect(() => {
Assert.IsFalse(commitFx);
commitFx = true;
});
});
Assert.IsTrue(commitFx);
bool outOfTransFx = false, outOfTransOnRollback = false;
Shield.SideEffect(() => outOfTransFx = true, () => outOfTransOnRollback = true);
Assert.IsTrue(outOfTransFx);
Assert.IsFalse(outOfTransOnRollback);
}
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 TransactionSafetyTest()
{
Shielded <int> a = new Shielded <int>(5);
Assert.AreEqual(5, a);
Assert.Throws <InvalidOperationException>(() =>
a.Modify((ref int n) => n = 10));
Assert.IsFalse(Shield.IsInTransaction);
Shield.InTransaction(() =>
{
a.Modify((ref int n) => n = 20);
// the TPL sometimes executes tasks on the same thread.
int x1 = 0;
var t = new Thread(() =>
{
Assert.IsFalse(Shield.IsInTransaction);
x1 = a;
});
t.Start();
t.Join();
Assert.IsTrue(Shield.IsInTransaction);
Assert.AreEqual(5, x1);
Assert.AreEqual(20, a);
});
Assert.IsFalse(Shield.IsInTransaction);
int x2 = 0;
var t2 = new Thread(() =>
{
Assert.IsFalse(Shield.IsInTransaction);
x2 = a;
});
t2.Start();
t2.Join();
Assert.AreEqual(20, x2);
Assert.AreEqual(20, a);
}
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 BasicTest()
{
var a = new Shielded<int>(10);
Shield.InTransaction(() => {
a.Value = 20;
Assert.AreEqual(20, a);
Shield.ReadOldState(() => {
Assert.AreEqual(10, a);
a.Value = 30;
Assert.AreEqual(10, a);
a.Modify((ref int x) =>
Assert.AreEqual(30, x));
});
Assert.AreEqual(30, a.Value);
});
Assert.AreEqual(30, a.Value);
}
public void BasicTest()
{
var a = new Shielded <int>(10);
Shield.InTransaction(() => {
a.Value = 20;
Assert.AreEqual(20, a);
Shield.ReadOldState(() => {
Assert.AreEqual(10, a);
a.Value = 30;
Assert.AreEqual(10, a);
a.Modify((ref int x) =>
Assert.AreEqual(30, x));
});
Assert.AreEqual(30, a.Value);
});
Assert.AreEqual(30, a.Value);
}
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 TransactionSafetyTest()
{
Shielded<int> a = new Shielded<int>(5);
Assert.AreEqual(5, a);
try
{
a.Modify((ref int n) => n = 10);
Assert.Fail();
}
catch (InvalidOperationException) {}
Assert.IsFalse(Shield.IsInTransaction);
Shield.InTransaction(() =>
{
a.Modify((ref int n) => n = 20);
// the TPL sometimes executes tasks on the same thread.
int x1 = 0;
var t = new Thread(() =>
{
Assert.IsFalse(Shield.IsInTransaction);
x1 = a;
});
t.Start();
t.Join();
Assert.IsTrue(Shield.IsInTransaction);
Assert.AreEqual(5, x1);
Assert.AreEqual(20, a);
});
Assert.IsFalse(Shield.IsInTransaction);
int x2 = 0;
var t2 = new Thread(() =>
{
Assert.IsFalse(Shield.IsInTransaction);
x2 = a;
});
t2.Start();
t2.Join();
Assert.AreEqual(20, x2);
Assert.AreEqual(20, a);
}
public void SkewWriteTest()
{
var cats = new Shielded<int>(1);
var dogs = new Shielded<int>(1);
int transactionCount = 0;
Task.WaitAll(
Enumerable.Range(1, 2).Select(i => Task.Factory.StartNew(() =>
Shield.InTransaction(() =>
{
Interlocked.Increment(ref transactionCount);
if (cats + dogs < 3)
{
Thread.Sleep(200);
if (i == 1)
cats.Modify((ref int n) => n++);
else
dogs.Modify((ref int n) => n++);
}
}), TaskCreationOptions.LongRunning)).ToArray());
Assert.AreEqual(3, cats + dogs);
Assert.AreEqual(3, transactionCount);
}
public void SideEffectTest()
{
var x = new Shielded<DateTime>(DateTime.UtcNow);
try
{
Shield.InTransaction(() =>
{
Shield.SideEffect(() => {
Assert.Fail("Suicide transaction has committed.");
},
() => {
throw new IgnoreMe();
});
// in case Assign() becomes commutative, we use Modify() to ensure conflict.
x.Modify((ref DateTime d) => d = DateTime.UtcNow);
var t = new Thread(() =>
Shield.InTransaction(() =>
x.Modify((ref DateTime d) => d = DateTime.UtcNow)));
t.Start();
t.Join();
});
Assert.Fail("Suicide transaction did not throw.");
}
catch (IgnoreMe) {}
bool commitFx = false;
Shield.InTransaction(() => {
Shield.SideEffect(() => {
Assert.IsFalse(commitFx);
commitFx = true;
});
});
Assert.IsTrue(commitFx);
}
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);
}
/// <summary>
/// Creates n events, with three typical offers (1,X,2) for each.
/// The events get IDs 1-n.
/// </summary>
public BetShop(int n)
{
List<Shielded<Event>> initialEvents = new List<Shielded<Event>>();
Shield.InTransaction(() =>
{
int eventIdGenerator = 1;
int offerIdGenerator = 1;
for (int i = 0; i < n; i++)
{
var newEvent = new Shielded<Event>(new Event()
{
Id = eventIdGenerator++,
HomeTeam = "Home " + i,
AwayTeam = "Away " + i
});
// we have to use Modify, because each offer needs a ref to the shielded
// event, which we do not have before that shielded event is constructed. And,
// after he is constructed, he can only be changed like this.
newEvent.Modify((ref Event e) =>
e.BetOffers = new ShieldedSeq<Shielded<BetOffer>>(
new Shielded<BetOffer>(new BetOffer()
{
Id = offerIdGenerator++,
Event = newEvent,
Pick = "1",
Odds = 2m
}),
new Shielded<BetOffer>(new BetOffer()
{
Id = offerIdGenerator++,
Event = newEvent,
Pick = "X",
Odds = 4m
}),
new Shielded<BetOffer>(new BetOffer()
{
Id = offerIdGenerator++,
Event = newEvent,
Pick = "2",
Odds = 4.5m
})));
initialEvents.Add(newEvent);
}
});
Events = new ShieldedDict<int, Shielded<Event>>(
initialEvents.Select(e => new KeyValuePair<int, Shielded<Event>>(e.Read.Id, e)));
}
public void Prioritization()
{
var x = new Shielded<int>();
var barrier = new Barrier(2);
int slowThread1Repeats = 0;
var slowThread1 = new Thread(() => {
barrier.SignalAndWait();
Shield.InTransaction(() => {
Interlocked.Increment(ref slowThread1Repeats);
int a = x;
Thread.Sleep(100);
x.Value = a - 1;
});
});
slowThread1.Start();
IDisposable conditional = null;
conditional = Shield.Conditional(() => { int i = x; return true; },
() => {
barrier.SignalAndWait();
Thread.Yield();
conditional.Dispose();
});
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
x.Modify((ref int a) => a++);
});
}
slowThread1.Join();
Assert.Greater(slowThread1Repeats, 1);
Assert.AreEqual(999, x);
// now, we introduce prioritization.
// this condition gets triggered before any attempt to write into x
int ownerThreadId = -1;
Shield.PreCommit(() => { int a = x; return true; }, () => {
var threadId = ownerThreadId;
if (threadId > -1 && threadId != Thread.CurrentThread.ManagedThreadId)
// we'll cause lower prio threads to busy wait. we could also
// add, e.g., an onRollback SideEffect which would wait for
// a certain signal before continuing the next iteration..
// (NB that Shield.SideEffect would, of course, have to be called
// before calling Rollback.)
Shield.Rollback();
});
// this will pass due to ownerThreadId == -1
Shield.InTransaction(() => x.Value = 0);
int slowThread2Repeats = 0;
var slowThread2 = new Thread(() => {
try
{
barrier.SignalAndWait();
Interlocked.Exchange(ref ownerThreadId, Thread.CurrentThread.ManagedThreadId);
Shield.InTransaction(() => {
Interlocked.Increment(ref slowThread2Repeats);
int a = x;
Thread.Sleep(100);
x.Value = a - 1;
});
}
finally
{
Interlocked.Exchange(ref ownerThreadId, -1);
}
});
slowThread2.Start();
conditional = Shield.Conditional(() => { int i = x; return true; },
() => {
barrier.SignalAndWait();
conditional.Dispose();
});
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
x.Modify((ref int a) => a++);
});
}
slowThread2.Join();
Assert.AreEqual(1, slowThread2Repeats);
Assert.AreEqual(999, x);
}
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));
}
static void ControlledRace()
{
var acc1 = new Shielded<Account>(new Account()
{
Id = 1,
Balance = 1000M,
Transfers = new List<Transfer>()
});
var acc2 = new Shielded<Account>(new Account()
{
Id = 2,
Balance = 1000M,
Transfers = new List<Transfer>()
});
int transactionCount = 0;
mtTest("controlled race", 20, n =>
{
if (n % 2 == 0)
return Task.Factory.StartNew(() =>
{
Shield.InTransaction(() =>
{
Interlocked.Increment(ref transactionCount);
Shield.SideEffect(() => Console.WriteLine("Transferred 100.00 .. acc1 -> acc2"),
() => Console.WriteLine("Task 1 rollback!"));
acc1.Modify((ref Account a) =>
{
a.Balance = a.Balance - 100M;
var list = a.Transfers;
Shield.SideEffect(() => list.Add(
new Transfer() { OtherId = acc2.Value.Id, AmountReceived = -100M }));
});
Thread.Sleep(100);
acc2.Modify((ref Account a) =>
{
a.Balance = a.Balance + 100M;
var list = a.Transfers;
Shield.SideEffect(() => list.Add(
new Transfer() { OtherId = acc1.Value.Id, AmountReceived = 100M }));
});
});
}, TaskCreationOptions.LongRunning);
else
return Task.Factory.StartNew(() =>
{
Shield.InTransaction(() =>
{
Interlocked.Increment(ref transactionCount);
Shield.SideEffect(() => Console.WriteLine("Transferred 200.00 .. acc1 <- acc2"),
() => Console.WriteLine("Task 2 rollback!"));
acc2.Modify((ref Account a) =>
{
a.Balance = a.Balance - 200M;
var list = a.Transfers;
Shield.SideEffect(() => list.Add(
new Transfer() { OtherId = acc1.Value.Id, AmountReceived = -200M }));
});
Thread.Sleep(250);
acc1.Modify((ref Account a) =>
{
a.Balance = a.Balance + 200M;
var list = a.Transfers;
Shield.SideEffect(() => list.Add(
new Transfer() { OtherId = acc2.Value.Id, AmountReceived = 200M }));
});
});
}, TaskCreationOptions.LongRunning);
});
Console.WriteLine("\nCompleted 20 transactions in {0} total attempts.", transactionCount);
Console.WriteLine("Account 1 balance: {0}", acc1.Value.Balance);
foreach (var t in acc1.Value.Transfers)
{
Console.WriteLine(" {0:####,00}", t.AmountReceived);
}
Console.WriteLine("\nAccount 2 balance: {0}", acc2.Value.Balance);
foreach (var t in acc2.Value.Transfers)
{
Console.WriteLine(" {0:####,00}", t.AmountReceived);
}
}
public static void MultiFieldOps()
{
long time;
_timer = Stopwatch.StartNew();
var numTrans = 100000;
var fields = 20;
Console.WriteLine(
"Testing multi-field ops with {0} iterations, and nuber of fields (N) = {1}",
numTrans, fields);
var accessTest = new Shielded<int>[fields];
for (int i = 0; i < fields; i++)
accessTest[i] = new Shielded<int>();
var dummy = new Shielded<int>();
time = _timer.ElapsedMilliseconds;
foreach (var k in Enumerable.Repeat(1, numTrans))
Shield.InTransaction(() => {
dummy.Value = 3;
var a = dummy.Value;
dummy.Modify((ref int n) => n = 5);
a = dummy.Value;
});
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("WARM UP in {0} ms.", time);
var results = new long[fields];
foreach (var i in Enumerable.Range(0, fields))
{
time = _timer.ElapsedMilliseconds;
foreach (var k in Enumerable.Repeat(1, numTrans))
Shield.InTransaction(() => {
for (int j = 0; j <= i; j++)
accessTest[j].Modify((ref int n) => n = 1);
});
results[i] = _timer.ElapsedMilliseconds - time;
Console.WriteLine("{0} field modifiers in {1} ms.", i + 1, results[i]);
}
}
public void Prioritization()
{
var x = new Shielded <int>();
var barrier = new Barrier(2);
// first, the version with no prioritization. the slow thread will repeat.
int slowThread1Repeats = 0;
var slowThread1 = new Thread(() => {
barrier.SignalAndWait();
Shield.InTransaction(() => {
Interlocked.Increment(ref slowThread1Repeats);
int a = x;
Thread.Sleep(100);
x.Value = a - 1;
});
});
slowThread1.Start();
IDisposable conditional = null;
conditional = Shield.Conditional(() => { int i = x; return(true); },
() => {
barrier.SignalAndWait();
Thread.Yield();
conditional.Dispose();
});
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
x.Modify((ref int a) => a++);
});
}
slowThread1.Join();
Assert.Greater(slowThread1Repeats, 1);
Assert.AreEqual(999, x);
// now, we introduce prioritization, using a simple lock
var lockObj = new object();
// this condition gets triggered just before any attempt to commit into x
Shield.PreCommit(() => { int a = x; return(true); }, () => {
// the simplest way to block low prio writers is just:
//lock (lockObj) { }
// but then the actual commit happens outside of the lock and may yet
// cause a conflict with someone just taking the lock. still, it's safer!
// and might be good enough for cases where a repetition won't hurt.
bool taken = false;
Action release = () =>
{
if (taken)
{
Monitor.Exit(lockObj);
taken = false;
}
};
// a bit of extra safety by using sync for the commit case.
Shield.SyncSideEffect(release);
Shield.SideEffect(null, release);
Monitor.Enter(lockObj, ref taken);
});
// not yet locked, so this is ok.
Shield.InTransaction(() => x.Value = 0);
int slowThread2Repeats = 0;
var slowThread2 = new Thread(() => {
barrier.SignalAndWait();
lock (lockObj)
{
Shield.InTransaction(() =>
{
Interlocked.Increment(ref slowThread2Repeats);
int a = x;
Thread.Sleep(100);
x.Value = a - 1;
});
}
});
slowThread2.Start();
conditional = Shield.Conditional(() => { int i = x; return(true); }, () => {
barrier.SignalAndWait();
conditional.Dispose();
});
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
x.Modify((ref int a) => a++);
});
}
slowThread2.Join();
Assert.AreEqual(1, slowThread2Repeats);
Assert.AreEqual(999, x);
}
public static void TreePoolTest()
{
int numThreads = 4;
int numItems = 200000;
// for some reason, if this is replaced with ShieldedDict, KeyAlreadyPresent
// exception is thrown. under one key you can then find an entity which does
// not have that key. complete mystery.
var tree = new ShieldedDict<Guid, TreeItem>();
var barrier = new Barrier(numThreads + 1);
int reportEvery = 10000;
Shielded<int> lastReport = new Shielded<int>(0);
Shielded<DateTime> lastTime = new Shielded<DateTime>(DateTime.UtcNow);
Shield.Conditional(() => tree.Count >= lastReport + reportEvery, () =>
{
DateTime newNow = DateTime.UtcNow;
int count = tree.Count;
int speed = (count - lastReport) * 1000 / (int)newNow.Subtract(lastTime).TotalMilliseconds;
lastTime.Assign(newNow);
lastReport.Modify((ref int n) => n += reportEvery);
Shield.SideEffect(() =>
{
Console.Write("\n{0} at {1} item/s", count, speed);
});
return true;
});
TreeItem x = new TreeItem();
_timer = new Stopwatch();
_timer.Start();
var time = _timer.ElapsedMilliseconds;
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => x.Id);
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("1 read transactions in {0} ms.", time);
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)
{
try
{
a();
}
catch
{
Console.Write(" * ");
}
}
barrier.SignalAndWait();
});
}
foreach (var i in Enumerable.Range(0, numItems))
{
var item1 = new TreeItem();
bags[i % numThreads].Add(() => Shield.InTransaction(() =>
{
tree.Add(item1.Id, item1);
}));
}
for (int i = 0; i < numThreads; i++)
threads[i].Start();
barrier.SignalAndWait();
time = _timer.ElapsedMilliseconds;
Console.WriteLine(" {0} ms.", time);
Console.WriteLine("\nReading sequentially...");
time = _timer.ElapsedMilliseconds;
var keys = Shield.InTransaction(() => tree.Keys);
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("Keys read in {0} ms.", time);
time = _timer.ElapsedMilliseconds;
Shield.InTransaction(() => {
foreach (var kvp in tree)
x = kvp.Value;
});
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("Items read by enumerator in {0} ms.", time);
time = _timer.ElapsedMilliseconds;
Shield.InTransaction(() => {
foreach (var k in keys)
x = tree[k];
});
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("Items read by key in one trans in {0} ms.", time);
time = _timer.ElapsedMilliseconds;
foreach (var k in keys)
x = tree[k];
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("Items read by key separately in {0} ms.", time);
time = _timer.ElapsedMilliseconds;
keys.AsParallel().ForAll(k => x = tree[k]);
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("Items read by key in parallel in {0} ms.", time);
time = _timer.ElapsedMilliseconds;
foreach (var k in Enumerable.Repeat(1, numItems))
Shield.InTransaction(() => x.Id);
time = _timer.ElapsedMilliseconds - time;
Console.WriteLine("1 read transactions in {0} ms.", time);
}
public int? BuyTicket(decimal payIn, params Shielded<BetOffer>[] bets)
{
var newId = Interlocked.Increment(ref _ticketIdGenerator);
var newTicket = new Shielded<Ticket>(new Ticket()
{
Id = newId,
PayInAmount = payIn
});
return Shield.InTransaction(() =>
{
newTicket.Modify((ref Ticket t) =>
{
t.Bets = bets.Select(shBo => new Bet()
{
Offer = shBo,
Odds = shBo.Read.Odds
}).ToArray();
t.WinAmount = t.PayInAmount *
t.Bets.Aggregate(1m, (curr, nextBet) => curr * nextBet.Odds);
});
var hash = GetOfferHash(newTicket);
var totalWin = _sameTicketWins.ContainsKey(hash) ?
_sameTicketWins[hash] + newTicket.Read.WinAmount : newTicket.Read.WinAmount;
if (totalWin > SameTicketWinLimit)
return false;
Tickets[newId] = newTicket;
_sameTicketWins[hash] = totalWin;
return true;
}) ? (int?)newId : null;
}
public static void Take()
{
Shield.InTransaction(() => _count.Modify((ref int c) => c--));
}
/// <summary>
/// Creates a BetShop, and tries to buy a large number of random tickets. Afterwards it
/// checks that the rule limiting same ticket winnings is not violated.
/// </summary>
public static void BetShopTest()
{
int numEvents = 100;
var betShop = new BetShop(numEvents);
var randomizr = new Random();
int reportEvery = 1000;
var lastReport = new Shielded<int>(0);
var lastTime = new Shielded<DateTime>(DateTime.UtcNow);
long time;
using (var reportingCond = 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);
});
}))
{
time = mtTest("bet shop w/ " + numEvents, 50000, i =>
{
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);
return Task.Factory.StartNew(() => 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);
}));
});
}
//}
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 SideEffectTest()
{
var x = new Shielded<DateTime>(DateTime.UtcNow);
try
{
Shield.InTransaction(() =>
{
Shield.SideEffect(() => {
Assert.Fail("Suicide transaction has committed.");
},
() => {
throw new IgnoreMe();
});
// in case Assign() becomes commutative, we use Modify() to ensure conflict.
x.Modify((ref DateTime d) => d = DateTime.UtcNow);
var t = new Thread(() =>
Shield.InTransaction(() =>
x.Modify((ref DateTime d) => d = DateTime.UtcNow)));
t.Start();
t.Join();
});
Assert.Fail("Suicide transaction did not throw.");
}
catch (AggregateException aggr)
{
Assert.AreEqual(1, aggr.InnerExceptions.Count);
Assert.AreEqual(typeof(IgnoreMe), aggr.InnerException.GetType());
}
bool commitFx = false;
Shield.InTransaction(() => {
Shield.SideEffect(() => {
Assert.IsFalse(commitFx);
commitFx = true;
});
});
Assert.IsTrue(commitFx);
bool outOfTransFx = false, outOfTransOnRollback = false;
Shield.SideEffect(() => outOfTransFx = true, () => outOfTransOnRollback = true);
Assert.IsTrue(outOfTransFx);
Assert.IsFalse(outOfTransOnRollback);
}
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 ConditionalTest()
{
var x = new Shielded <int>();
var testCounter = 0;
var triggerCommits = 0;
Shield.Conditional(() => {
Interlocked.Increment(ref testCounter);
return(x > 0 && (x & 1) == 0);
},
() => {
Shield.SideEffect(() =>
Interlocked.Increment(ref triggerCommits));
Assert.IsTrue(x > 0 && (x & 1) == 0);
});
const int count = 1000;
ParallelEnumerable.Repeat(1, count).ForAll(i =>
Shield.InTransaction(() => x.Modify((ref int n) => n++)));
// one more, for the first call to Conditional()! btw, if this conditional were to
// write anywhere, he might conflict, and an interlocked counter would give more due to
// repetitions. so, this confirms reader progress too.
Assert.AreEqual(count + 1, testCounter);
// every change triggers it, but by the time it starts, another transaction might have
// committed, so this is not a fixed number.
Assert.Greater(triggerCommits, 0);
// a conditional which does not depend on any Shielded is not allowed!
int a = 5;
Assert.Throws <InvalidOperationException>(() =>
Shield.Conditional(() => a > 10, () => { }));
bool firstTime = true;
var x2 = new Shielded <int>();
// this one succeeds in registering, but fails as soon as it gets triggered, due to changing it's
// test's access pattern to an empty set.
Shield.Conditional(() => {
if (firstTime)
{
firstTime = false;
return(x2 == 0);
}
else
{
// this is of course invalid, and when reaching here we have not touched any Shielded obj.
return(true);
}
}, () => { });
try
{
// this will trigger the conditional
Shield.InTransaction(() => x2.Modify((ref int n) => n++));
Assert.Fail();
}
catch (AggregateException aggr)
{
Assert.AreEqual(1, aggr.InnerExceptions.Count);
Assert.AreEqual(typeof(InvalidOperationException), aggr.InnerException.GetType());
}
}
static void OneTransaction()
{
Shielded<int> sh = new Shielded<int>();
Shield.InTransaction(() =>
{
int x = sh;
Console.WriteLine("Value: {0}", x);
sh.Modify((ref int a) => a = x + 1);
Console.WriteLine("Value after increment: {0}", sh.Value);
});
}
public void Prioritization()
{
var x = new Shielded <int>();
var barrier = new Barrier(2);
int slowThread1Repeats = 0;
var slowThread1 = new Thread(() => {
barrier.SignalAndWait();
Shield.InTransaction(() => {
Interlocked.Increment(ref slowThread1Repeats);
int a = x;
Thread.Sleep(100);
x.Value = a - 1;
});
});
slowThread1.Start();
IDisposable conditional = null;
conditional = Shield.Conditional(() => { int i = x; return(true); },
() => {
barrier.SignalAndWait();
Thread.Yield();
conditional.Dispose();
});
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
x.Modify((ref int a) => a++);
});
}
slowThread1.Join();
Assert.Greater(slowThread1Repeats, 1);
Assert.AreEqual(999, x);
// now, we introduce prioritization.
// this condition gets triggered before any attempt to write into x
int ownerThreadId = -1;
Shield.PreCommit(() => { int a = x; return(true); }, () => {
var threadId = ownerThreadId;
if (threadId > -1 && threadId != Thread.CurrentThread.ManagedThreadId)
{
// we'll cause lower prio threads to busy wait. we could also
// add, e.g., an onRollback SideEffect which would wait for
// a certain signal before continuing the next iteration..
// (NB that Shield.SideEffect would, of course, have to be called
// before calling Rollback.)
Shield.Rollback();
}
});
// this will pass due to ownerThreadId == -1
Shield.InTransaction(() => x.Value = 0);
int slowThread2Repeats = 0;
var slowThread2 = new Thread(() => {
try
{
barrier.SignalAndWait();
Interlocked.Exchange(ref ownerThreadId, Thread.CurrentThread.ManagedThreadId);
Shield.InTransaction(() => {
Interlocked.Increment(ref slowThread2Repeats);
int a = x;
Thread.Sleep(100);
x.Value = a - 1;
});
}
finally
{
Interlocked.Exchange(ref ownerThreadId, -1);
}
});
slowThread2.Start();
conditional = Shield.Conditional(() => { int i = x; return(true); },
() => {
barrier.SignalAndWait();
conditional.Dispose();
});
foreach (int i in Enumerable.Range(1, 1000))
{
Shield.InTransaction(() => {
x.Modify((ref int a) => a++);
});
}
slowThread2.Join();
Assert.AreEqual(1, slowThread2Repeats);
Assert.AreEqual(999, x);
}
