Charting Multiple Processor Activity

Logging and charting are similar for both multiple processor systems and single-processor systems. And because the graphs can get crowded and complex, its best to log the System, Processor, Process, and Thread objects, and then chart them one at a time. If you need to compare charts, start several copies of Performance Monitor and have them all chart or report on data from the same log file.

When monitoring a complex occurrence, a comparison of graphs can be more useful than a single graph.

• A chart of System: % Total Processor Time shows the overall performance of the system. This curve flattens into a horizontal line in a multiprocessor bottleneck.

• A chart of Processor: % Processor Time for each processor shows patterns of processor use. You can determine each processor's start time, as well as its utilization. Use bookmarks when you start processes to see the effect they have on the processors. The sum of Processor: % Processor Time for each processor is System: % Total Processor Time.

• A chart or histogram of Process: % Processor Time for all active processes reveals processor use by operating system services and network support, not to mention Performance Monitor.

• A Thread: % Processor Time chart is essential for diagnosing the processor problems. Although the operating system executes processes, the threads send instructions to the processors. Also, Thread: % Processor Time is a better indicator of processor use than Process: % Processor Time, because the latter has a maximum value of 100%.

Compare a Thread: % Processor Time chart with a Processor: % Processor Time chart. You can match the threads to their processors because their curves have similar shapes and values. You can also determine which threads are doing background work and which are contending for the foreground.

A chart of Thread: % Processor Time for all threads on a busy system is likely to be confusing, so chart the threads of each process separately, either one at a time, or with different copies of Performance Monitor reading the same log file.

You can also test each of your processors independently or in different combinations with single and multithreaded applications. Add Process: Thread Count to a Performance Monitor report to see how many threads are in each active process. Edit the Boot.ini file in your root directory to change the number and combination of active processors.

Task Manager, a new administrative tool, lets you determine which processes run on which processors of a multiprocessor computer. On the Task Manager Processes tab, click a process with the right mouse button, then select Set Affinity. The process you selected will run only on the processors selected on the panel. This is a great testing tool.