Class SslBufferPool

java.lang.Object
org.jboss.netty.handler.ssl.SslBufferPool

public class SslBufferPool extends Object
A ByteBuffer pool dedicated for SslHandler performance improvement.

In most cases, you won't need to create a new pool instance because SslHandler has a default pool instance internally.

The reason why SslHandler requires a buffer pool is because the current SSLEngine implementation always requires a 17KiB buffer for every 'wrap' and 'unwrap' operation. In most cases, the actual size of the required buffer is much smaller than that, and therefore allocating a 17KiB buffer for every 'wrap' and 'unwrap' operation wastes a lot of memory bandwidth, resulting in the application performance degradation.

  • Field Details

    • MAX_PACKET_SIZE_ALIGNED

      private static final int MAX_PACKET_SIZE_ALIGNED
      See Also:
    • DEFAULT_POOL_SIZE

      private static final int DEFAULT_POOL_SIZE
      See Also:
    • preallocated

      private final ByteBuffer preallocated
    • pool

      private final BlockingQueue<ByteBuffer> pool
    • maxBufferCount

      private final int maxBufferCount
    • allocateDirect

      private final boolean allocateDirect
    • numAllocations

      private final AtomicInteger numAllocations
      The number of buffers allocated so far. Used only when preallocated is null.
  • Constructor Details

    • SslBufferPool

      public SslBufferPool()
      Creates a new buffer pool whose size is 19267584, which can hold 1024 buffers.
    • SslBufferPool

      public SslBufferPool(boolean preallocate, boolean allocateDirect)
      Creates a new buffer pool whose size is 19267584, which can hold 1024 buffers.
      Parameters:
      preallocate - true if and only if the buffers in this pool has to be pre-allocated at construction time
      allocateDirect - true if and only if this pool has to allocate direct buffers.
    • SslBufferPool

      public SslBufferPool(int maxPoolSize)
      Creates a new buffer pool.
      Parameters:
      maxPoolSize - the maximum number of bytes that this pool can hold
    • SslBufferPool

      public SslBufferPool(int maxPoolSize, boolean preallocate, boolean allocateDirect)
      Creates a new buffer pool.
      Parameters:
      maxPoolSize - the maximum number of bytes that this pool can hold
      preallocate - true if and only if the buffers in this pool has to be pre-allocated at construction time
      allocateDirect - true if and only if this pool has to allocate direct buffers.
  • Method Details

    • getMaxPoolSize

      public int getMaxPoolSize()
      Returns the maximum size of this pool in byte unit. The returned value can be somewhat different from what was specified in the constructor.
    • getUnacquiredPoolSize

      public int getUnacquiredPoolSize()
      Returns the number of bytes which were allocated but have not been acquired yet. You can estimate how optimal the specified maximum pool size is from this value. If it keeps returning 0, it means the pool is getting exhausted. If it keeps returns a unnecessarily big value, it means the pool is wasting the heap space.
    • acquireBuffer

      public ByteBuffer acquireBuffer()
      Acquire a new ByteBuffer out of the SslBufferPool
    • releaseBuffer

      public void releaseBuffer(ByteBuffer buffer)
      Release a previous acquired ByteBuffer
    • allocate

      private ByteBuffer allocate(int capacity)