| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hbase.io.asyncfs; |
| |
| import org.apache.yetus.audience.InterfaceAudience; |
| |
| /** |
| * Used to predict the next send buffer size. |
| */ |
| @InterfaceAudience.Private |
| class SendBufSizePredictor { |
| |
| // LIMIT is 128MB |
| private static final int LIMIT = 128 * 1024 * 1024; |
| |
| // buf's initial capacity - 4KB |
| private int capacity = 4 * 1024; |
| |
| int initialSize() { |
| return capacity; |
| } |
| |
| int guess(int bytesWritten) { |
| // if the bytesWritten is greater than the current capacity |
| // always increase the capacity in powers of 2. |
| if (bytesWritten > this.capacity) { |
| // Ensure we don't cross the LIMIT |
| if ((this.capacity << 1) <= LIMIT) { |
| // increase the capacity in the range of power of 2 |
| this.capacity = this.capacity << 1; |
| } |
| } else { |
| // if we see that the bytesWritten is lesser we could again decrease |
| // the capacity by dividing it by 2 if the bytesWritten is satisfied by |
| // that reduction |
| if ((this.capacity >> 1) >= bytesWritten) { |
| this.capacity = this.capacity >> 1; |
| } |
| } |
| return this.capacity; |
| } |
| } |