VizDIET

VizDIET is the monitoring tool written for DIET to be able to vizualize and analyze the status and activities of a running DIET deployment. As described in Section 12.1, all DIET's components integrate a LogComponent, and VizDIET implements the LogTool interface in order to be able to collect all information sent by DIET's components through their LogComponent.

VizDIET provides a graphic representation of the DIET architecture being monitored. There are two ways to use VizDIET.

Real-time monitoring:

VizDIET is directly connected to the LogCentral using a Corba connection and receives directly all information about the running DIET platform.

Post-mortem monitoring:

VizDIET reads a log file containing all log messages received by LogCentral. This post-mortem analysis can also be replayed in real time if the log file is time sorted. The log file is created during the real deployment by a special tool provided with LogService that receives all messages from LogCentral and writes them to a file.

Figure 12.2: Snapshot of VizDIET.

As described in Section 1.4, there are two main steps in the treatment of a request in DIET: one step to find and schedule a service, and one step to solve this service. So two main activities are represented: schedule and compute information

Schedule information

:
When an agent takes a scheduling decision for a task (i.e., finding and deciding which SeD can execute a service), it is useful to know how the agent made its decision. This information is represented by FindRequest in VizDIET.

Compute information

:
When a SeD is computing a job we need to be aware of its state and know when the computation begins and ends. This information is represented by SolveRequest. In VizDIET, when a SeD is solving a service, the SeD changes color to red.

Figure 12.3: Bar, taskflow and gantt graphs in vizDIET.

FindRequests are only attached to agents and SolveRequests are only attached to SeDs. Finally the aggregation of one FindRequest and its SolveRequest is concatenated in one request: DIETRequest. DIETResquest can be see as a job execution in a DIET platform as seen by an end-user. A DIETRequest is also associated with a latency, which is time between the end of a FindRequest and the beginning of a SolveRequest.

VizDIET offers the possiblity to visualize all of these requests from either the point of view of the DIET platform, in which case you will see the DIETRequests, or in the point of view of the Agents or SeDs, in which case you will see respectively the FindRequest and the SolveRequest. The different kinds of requests are represented in different types of graphics such as a Gantt chart, taskflow chart, or bar chart.

VizDIET also computes some other statistics for the platform such as average time for scheduling, for solving, or latency. This information can be see for the whole service in the platform or for one specific service. VizDIET has one other interesting feature: the possibility to export all data collected by VizDIET into a file using a format that you specify.

Finally, VizDIET is quite useful for understanding the behavior of the DIET hierarchy and quite simple to use. You have to keep in mind that VizDIET bases its information upon log information that is forwarded by LogCentral from DIET components. Therefore, the information displayed and computed in VizDIET is limited to the DIET hierarchy (e.g., there is no information about clients).

Future development of VizDIET will depend on new developments in DIET. For example, a new integration between DIET and JuxMem allows DIET to store data in the JuxMem service. Correspondingly, the capability to log and visualize these transfers has been added to VizDIET. VizDIET is available for download. See the web page http://graal.ens-lyon.fr/DIET/vizdiet.html for more information.