Speed data reader in PyramidBox model.
Created by: qingqing01
The data reader is very time-consuming.
测试数据：
| 实验 | GPU个数 | BatchSize/GPU | 是否Load Data | 数据处理+拷贝 | Run时间 | 10个batch的时间 |
|---|---|---|---|---|---|---|
| Executor | 1 | 5 | Yes | 7.45 | 18.94 | 27.12 |
| Executor | 1 | 5 | No | 0 | 18.77 | 19.60 |
| ParallelExe | 2 | 5 | Yes | 16.03 | 25.96 | 41.99 |
| ParallelExe | 2 | 5 | No | 0 | 25.56 | 25.57 |
| ParallelExe | 4 | 5 | Yes | 31.15 | 32.43 | 63.58 |
| ParallelExe | 4 | 5 | No | 0 | 30.48 | 30.47 |