Generally, it is not easy for us to understand behavior of a parallel program being executed on a parallel machine having hundreds of element processors like the PIM.
As behavior of application programs for knowledge processing is usually irregular, it is difficult to predict in advance the amount of their computational load and the timing the load is generated.
Thus, we have to anticipate the behavior of the program and make division and distribution of the anticipated computational load.
After that, using the run-time monitor, we actually run the program on the PIM and observe its load balancing among element processors. If the result is unsatisfactory, we modify the program and repeat this process until we obtain a satisfactory result. We call this process as "performance degugging".
We collected several run-time monitor displays below. You can see that one job is dynamically divided into several sub-processes and they are propagated among many element processors. These displays are actually seen as an animation film.
Structure of the display is different for PIM/m or PIM/p depending on its interconnection mechanism. PIM/m has a two dimensional mesh structure for its interconnection. PIM/p has "clusters" each of which contains 8 element processor connected with a shared memory. 64 of these clusters are connected with a network.
With the run-time monitor displays for PIM/m, you can see 256 element processor in one rectangular Its vertical axis indicates numbers from 0 to 255 which specify 256 element processors. Its horizontal axis is time. In every 2 seconds, change of the computational load is shown using colors. The red means 100% busy and blue means idle.
With the displays for PIM/p, you can see 64 rectangular boxes which correspond to 64 clusters. Each of these boxes is vertically divided into 8 rows corresponding to 8 element processors. In each row, change of the load is shown in every 2 seconds.
Generally, in the beginning of program execution, you see blue and green in the display. In the middle , you see yellow and red. Finally, you see green and blue again.
In execution of another program which activates many element processors one time, you see that colors change from blue to red instantly.
Please enjoy run-time monitor displays below.
