public unsafe void CouldAcquireReleaseExclusiveLock()
{
var ptr = (long *)Marshal.AllocHGlobal(8);
* ptr = 0;
var wpid = Wpid.Create();
var wpid2 = Wpid.Create();
var sl = new SharedSpinLock(ptr);
Assert.AreEqual(Wpid.Empty, sl.TryAcquireExclusiveLock(wpid, out _, spinLimit: 0)); // fast path
Assert.AreEqual(Wpid.Empty, sl.TryReleaseLock(wpid));
Assert.AreEqual(Wpid.Empty, sl.TryAcquireExclusiveLock(wpid, out _));
var sw = new Stopwatch();
sw.Start();
Assert.AreEqual(wpid, sl.TryAcquireExclusiveLock(wpid2, out _, spinLimit: 1000));
sw.Stop();
Console.WriteLine($"Elapsed: {sw.ElapsedMilliseconds}");
Assert.AreEqual(Wpid.Empty, sl.TryReleaseLock(wpid));
}
public unsafe void UncontentedBench()
{
var ptr = (long *)Marshal.AllocHGlobal(8);
* ptr = 0;
var wpid = Wpid.Create();
var sl = new SharedSpinLock(ptr);
var count = 10_000_000;
for (int _ = 0; _ < 10; _++)
{
using (Benchmark.Run("Uncontented", count))
{
for (int i = 0; i < count; i++)
{
sl.TryAcquireLock(wpid);
sl.TryReleaseLock(wpid);
}
}
}
Benchmark.Dump();
}
/// <summary>
/// Increment shared instance id and return a process buffer with new Wpid
/// </summary>
/// <returns></returns>
public ProcessConfigRecord CreateNew()
{
using (var txn = Environment.BeginTransaction())
{
while (true)
{
// ReSharper disable once ImpureMethodCallOnReadonlyValueField
var newInsatnceId = unchecked ((uint)SharedRecord._processBuffer.InterlockedIncrementInt32(ProcessConfigRecord.SharedInstanceIdCounterOffset));
try
{
// We try to increment instance id instead of reuse existing
// At some point after running for very very long time it might overflow
// and start from zero again - this is fine.
if (_processDb.TryGet(txn, ref newInsatnceId, out BufferRef bufferRef))
{
continue;
}
bufferRef = Allocate(txn, 0, out var fromFreeList, null);
_processDb.Put(txn, newInsatnceId, bufferRef, TransactionPutOptions.NoOverwrite);
txn.Commit();
if (!fromFreeList)
{
Environment.Sync(true);
}
var result = _buckets[bufferRef];
if (fromFreeList)
{
// in Delete we clear the buffer after commit, there is small chance a process died after commit but before cleaning
result.Clear(0, result.Length);
}
else
{
Debug.Assert(result.IsFilledWithValue(0), "a new ProcessConfig buffer must be clean.");
}
result.WriteInt64(ProcessConfigRecord.WpidOffset, Wpid.Create(newInsatnceId));
var record = new ProcessConfigRecord(result);
return(record);
}
catch (Exception ex)
{
txn.Abort();
Trace.TraceError(ex.ToString());
throw;
}
}
}
}
public unsafe void CouldAcquireEnterExitReleaseExclusiveLock()
{
var ptr = (long *)Marshal.AllocHGlobal(8);
* ptr = 0;
var wpid = Wpid.Create();
var wpid2 = Wpid.Create();
var sl = new SharedSpinLock(ptr);
Assert.AreEqual(Wpid.Empty, sl.TryAcquireExclusiveLock(wpid, out var tt, spinLimit: 0));
Assert.AreEqual(Wpid.Empty, sl.TryReEnterExclusiveLock(wpid, tt, spinLimit: 0));
Assert.Throws <InvalidOperationException>(() => { sl.TryReleaseLock(wpid); });
Assert.AreEqual(Wpid.Empty, sl.TryExitExclusiveLock(wpid, tt));
Assert.AreEqual(Wpid.Empty, sl.TryReleaseLock(wpid));
}
public unsafe void ReleasingOthersLockReturnsOthersWpid()
{
var ptr = (long *)Marshal.AllocHGlobal(8);
* ptr = 0;
var wpid = Wpid.Create();
var wpid2 = Wpid.Create();
var sl = new SharedSpinLock(ptr);
Assert.AreEqual(Wpid.Empty, sl.TryAcquireLock(wpid, spinLimit: 0)); // fast path
Assert.AreEqual(Wpid.Empty, sl.TryReleaseLock(wpid));
Assert.AreEqual(Wpid.Empty, sl.TryAcquireLock(wpid));
// wpid holding the lock
var holder = sl.TryReleaseLock(wpid2);
Assert.AreEqual(wpid, holder);
}