Xen Monitoring Tool (disk and cpu) & Xen 4.0

On Tuesday I continued working on the monitoring app: disk and cpu metrics are now gathered and written to file. Also to make sure the tap:aio interface worked correctly when starting VMs, I had to install a newer Xen version (4.0). The way the application works now is by first calling the start operation on the XenBaked, IOStat and OProfile controllers, then a given command is executed on the specified VMs before going to sleep for the given duration. Afterwards the stop method of the controllers is called, followed by a report (write output to file) and parse (get the desired information from the output files) call for the different tools. Finally this disk, cpu and cache information is written to file. Working this way makes sure IO load is only generated after the experiment is finished, by writing to file when report is called after the monitoring has stopped. Also the tool is lightweight because the parsing of the output and creation of the actual output file can be performed on a separate machine. What's next? Finishing the prototype of the monitoring tool by completing the cache hits and misses information. And making sure the results are correct, by running the app under certain VM workloads.