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improved asyncpool usability...
improved asyncpool usability working on batch operations on asyncqueue
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r120:f1b897999260 v2
r120:f1b897999260 v2
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AsyncQueue.cs
271 lines | 7.7 KiB | text/x-csharp | CSharpLexer
/ Implab / Parallels / AsyncQueue.cs
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cin
Promises rewritten, added improved version of AsyncQueue
 r119 using System.Threading;
using System.Collections.Generic;
using System;
using System.Collections;
namespace Implab.Parallels {
public class AsyncQueue<T> : IEnumerable<T> {
class Chunk {
public Chunk next;
int m_low;
int m_hi;
int m_alloc;
readonly int m_size;
readonly T[] m_data;
public Chunk(int size) {
m_size = size;
m_data = new T[size];
}
public Chunk(int size, T value) {
m_size = size;
m_hi = 1;
m_alloc = 1;
m_data = new T[size];
m_data[0] = value;
}
public int Low {
get { return m_low; }
}
public int Hi {
get { return m_hi; }
}
public bool TryEnqueue(T value,out bool extend) {
cin
improved asyncpool usability...
 r120 var alloc = Interlocked.Increment(ref m_alloc) - 1;
cin
Promises rewritten, added improved version of AsyncQueue
 r119
cin
improved asyncpool usability...
 r120 if (alloc >= m_size) {
extend = alloc == m_size;
cin
Promises rewritten, added improved version of AsyncQueue
 r119 return false;
}
cin
improved asyncpool usability...
 r120
extend = false;
cin
Promises rewritten, added improved version of AsyncQueue
 r119 m_data[alloc] = value;
while (alloc != Interlocked.CompareExchange(ref m_hi, alloc + 1, alloc)) {
// spin wait for commit
}
return true;
}
public bool TryDequeue(out T value,out bool recycle) {
int low;
do {
low = m_low;
if (low >= m_hi) {
value = default(T);
recycle = (low == m_size);
return false;
}
} while(low != Interlocked.CompareExchange(ref m_low, low + 1, low));
recycle = (low == m_size - 1);
value = m_data[low];
return true;
}
cin
improved asyncpool usability...
 r120 public bool TryEnqueueBatch(T[] batch, int offset, int length, out int enqueued, out bool extend) {
int alloc;
int allocSize;
do {
alloc = m_alloc;
if (alloc > m_size) {
enqueued = 0;
extend = false;
return false;
}
allocSize = Math.Min(m_size - m_alloc, length);
} while(alloc != Interlocked.CompareExchange(ref m_alloc, alloc + allocSize, alloc));
if (alloc == m_size) {
enqueued = 0;
extend = true;
return false;
}
Array.Copy(batch, offset, m_data, alloc, allocSize);
enqueued = allocSize;
extend = false;
while (alloc != Interlocked.CompareExchange(ref m_hi, alloc + allocSize, alloc)) {
// spin wait for commit
}
return true;
}
cin
Promises rewritten, added improved version of AsyncQueue
 r119 public T GetAt(int pos) {
return m_data[pos];
}
}
public const int DEFAULT_CHUNK_SIZE = 32;
readonly int m_chunkSize = DEFAULT_CHUNK_SIZE;
Chunk m_first;
Chunk m_last;
public AsyncQueue() {
m_last = m_first = new Chunk(m_chunkSize);
}
public void Enqueue(T value) {
var last = m_last;
// spin wait to the new chunk
bool extend = true;
while(last == null || !last.TryEnqueue(value, out extend)) {
// try to extend queue
if (extend || last == null) {
var chunk = new Chunk(m_chunkSize, value);
if (EnqueueChunk(last, chunk))
break;
last = m_last;
} else {
while (last != m_last) {
Thread.MemoryBarrier();
last = m_last;
}
}
}
}
public bool TryDequeue(out T value) {
var chunk = m_first;
bool recycle;
while (chunk != null) {
var result = chunk.TryDequeue(out value, out recycle);
if (recycle) // this chunk is waste
RecycleFirstChunk(chunk);
else
return result; // this chunk is usable and returned actual result
if (result) // this chunk is waste but the true result is always actual
return true;
// try again
chunk = m_first;
}
// the queue is empty
value = default(T);
return false;
}
bool EnqueueChunk(Chunk last, Chunk chunk) {
if (Interlocked.CompareExchange(ref m_last, chunk, last) != last)
return false;
if (last != null)
last.next = chunk;
else
m_first = chunk;
return true;
}
void RecycleFirstChunk(Chunk first) {
var next = first.next;
if (next == null) {
// looks like this is the last chunk
if (first != Interlocked.CompareExchange(ref m_last, null, first)) {
// race
// maybe someone already recycled this chunk
// or a new chunk has been appedned to the queue
return; // give up
}
// the tail is updated
}
// we need to update the head
Interlocked.CompareExchange(ref m_first, next, first);
// if the head is already updated then give up
return;
}
#region IEnumerable implementation
class Enumerator : IEnumerator<T> {
Chunk m_current;
int m_pos = -1;
public Enumerator(Chunk fisrt) {
m_current = fisrt;
}
#region IEnumerator implementation
public bool MoveNext() {
if (m_current == null)
return false;
if (m_pos == -1)
m_pos = m_current.Low;
else
m_pos++;
if (m_pos == m_current.Hi) {
m_pos = 0;
m_current = m_current.next;
}
return true;
}
public void Reset() {
throw new NotSupportedException();
}
object IEnumerator.Current {
get {
return Current;
}
}
#endregion
#region IDisposable implementation
public void Dispose() {
}
#endregion
#region IEnumerator implementation
public T Current {
get {
if (m_pos == -1 || m_current == null)
throw new InvalidOperationException();
return m_current.GetAt(m_pos);
}
}
#endregion
}
public IEnumerator<T> GetEnumerator() {
return new Enumerator(m_first);
}
#endregion
#region IEnumerable implementation
IEnumerator IEnumerable.GetEnumerator() {
return GetEnumerator();
}
#endregion
}
}