/// <summary>
/// Get textual statistics about the buffer pool.
/// </summary>
public static string GetStatistics(bool showEmptyBuffers = true)
{
rwLock.EnterReadLock();
try
{
statiscticsBuilder.Length = 0;
statiscticsBuilder.AppendFormat("Pooled array reused count: {0:N0}\n", GetBuffers);
statiscticsBuilder.AppendFormat("Release call count: {0:N0}\n", ReleaseBuffers);
statiscticsBuilder.AppendFormat("PoolSize: {0:N0}\n", PoolSize);
statiscticsBuilder.AppendFormat("Buffers: {0}\n", FreeBuffers.Count);
for (int i = 0; i < FreeBuffers.Count; ++i)
{
BufferStore store = FreeBuffers[i];
List <BufferDesc> buffers = store.buffers;
if (showEmptyBuffers || buffers.Count > 0)
{
statiscticsBuilder.AppendFormat("- Size: {0:N0} Count: {1:N0}\n", store.Size, buffers.Count);
}
}
return(statiscticsBuilder.ToString());
}
finally
{
rwLock.ExitReadLock();
}
}
/// <summary>
/// Internal function called by the plugin to remove old, non-used buffers.
/// </summary>
internal static void Maintain()
{
DateTime now = DateTime.UtcNow;
if (!_isEnabled || lastMaintenance + RunMaintenanceEvery > now)
{
return;
}
lastMaintenance = now;
DateTime olderThan = now - RemoveOlderThan;
rwLock.EnterWriteLock();
try
{
//if (HTTPManager.Logger.Level == Logger.Loglevels.All)
// HTTPManager.Logger.Information("VariableSizedBufferPool", "Before Maintain: " + GetStatistics());
for (int i = 0; i < FreeBuffers.Count; ++i)
{
BufferStore store = FreeBuffers[i];
List <BufferDesc> buffers = store.buffers;
for (int cv = buffers.Count - 1; cv >= 0; cv--)
{
BufferDesc desc = buffers[cv];
if (desc.released < olderThan)
{
// buffers stores available buffers ascending by age. So, when we find an old enough, we can
// delete all entries in the [0..cv] range.
int removeCount = cv + 1;
buffers.RemoveRange(0, removeCount);
PoolSize -= (int)(removeCount * store.Size);
break;
}
}
if (RemoveEmptyLists && buffers.Count == 0)
{
FreeBuffers.RemoveAt(i--);
}
}
//if (HTTPManager.Logger.Level == Logger.Loglevels.All)
// HTTPManager.Logger.Information("VariableSizedBufferPool", "After Maintain: " + GetStatistics());
}
finally
{
rwLock.ExitWriteLock();
}
}
private static void AddFreeBuffer(byte[] buffer)
{
int bufferLength = buffer.Length;
for (int i = 0; i < FreeBuffers.Count; ++i)
{
BufferStore store = FreeBuffers[i];
if (store.Size == bufferLength)
{
// We highly assume here that every buffer will be released only once.
// Checking for double-release would mean that we have to do another O(n) operation, where n is the
// count of the store's elements.
if (IsDoubleReleaseCheckEnabled)
{
for (int cv = 0; cv < store.buffers.Count; ++cv)
{
if (store.buffers[cv].buffer == buffer)
{
HTTPManager.Logger.Error("VariableSizedBufferPool", "Buffer already added to the pool!");
return;
}
}
}
store.buffers.Add(new BufferDesc(buffer));
return;
}
if (store.Size > bufferLength)
{
FreeBuffers.Insert(i, new BufferStore(bufferLength, buffer));
return;
}
}
// When we reach this point, there's no same sized or larger BufferStore present, so we have to add a new one
// to the endo of our list.
FreeBuffers.Add(new BufferStore(bufferLength, buffer));
}
private static BufferDesc FindFreeBuffer(long size, bool canBeLarger)
{
for (int i = 0; i < FreeBuffers.Count; ++i)
{
BufferStore store = FreeBuffers[i];
if (store.buffers.Count > 0 && (store.Size == size || (canBeLarger && store.Size > size)))
{
// Getting the last one has two desired effect:
// 1.) RemoveAt should be quicker as it don't have to move all the remaining entries
// 2.) Old, non-used buffers will age. Getting a buffer and putting it back will not keep buffers fresh.
BufferDesc lastFree = store.buffers[store.buffers.Count - 1];
store.buffers.RemoveAt(store.buffers.Count - 1);
return(lastFree);
}
}
return(BufferDesc.Empty);
}
