Ns2 project in Alberta
Ns2 project in Alberta probes directly access the address spaces of individual processes on that node, thereby providing a convenient mechanism for amp ling.The main advantage of probes over sampled sensors is that the application code ns2 project in Alberta need not be changed for probing, so that the information to be probed may be defined dynamically. Furthermore, when monitoring parallel programs ns2 project in Alberta executing on shared memory machines, the use of probes versus sensors can reduce program perturbation due to monitoring Any monitoring system must address ns2 project in Alberta the storage of the program information it produces.
Since the primary use of our monitor is dynamic monitoring, we first store all monitoring information in data structures mapped to main memory using the operating system’s virtual memory mechanisms, thereby reducing ns2 project in Alberta the latency of access to such information. For performance reasons, this ns2 project in Alberta collected data, termed the database, does not contain raw data. It contains analyzed data derived from the information collected using sensors and probes. All information stored in the database is tagged with time stamps and locations of occurrence, for use ns2 project in Alberta by dynamic and post-execution analysis of monitoring information.
The data structures being used are straightforward template structures derived from the information model used for description of monitoring information. Although the virtual memory database can grow to significant size, for long-term persistent information storage, we currently use ad hoc ns2 project in Alberta file structures, but would prefer using a large-scale historical database in order to be able to perform efficient, additional post-execution analyses. Sample post-execution analysis of such stored information may concern additional analysis of interest to the ns2 project in Alberta programmer or the adaptation algorithms, or it may concern the reproduction or replay of program execution .