User`s guide

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System Performance Analysis (SPA) Software
System Performance Analysis Software
Example State Histogram example
A computer system has several I/O devices, such as a data terminal,
disk drive, tape drive, and printer. Each device has its own service
routines stored in memory. The problem is that one or more of the
devices is tying up the CPU.
The address bus of the system is monitored using State Histogram to
define the memory blocks where the service routines are stored. The
histograms quickly show that the print spooler is not working because
the printer is constantly interrupting the CPU and is consuming 80% of
address bus activity.
The figure below shows a sample State Histogram display.
SPA State Histogram Menu