DSCOPE: PERFORMANCE ANALYZER AND MONITOR

QUESTION

Why doesn't the performance analyzer work when I use dScope to debug my program with a monitor like the Keil MON51, MON251, or MON166 or the Intel RISM51, RISM251, or RISM930?

ANSWER

dScope only allows the Performance Analyzer to be used when you simulate your target using one of the CPU driver DLLs. When you use a monitor interface DLL (like MON51, MON251, MON166, RISM51, RISM251, or RISM930), dScope disables Performance Analysis.

When you perform target debugging, dScope uses your PC's serial port to communicate with a monitor program running on your target board. The serial port is usually configured to run at somewhere between 9600 and 57600 baud.

To analyze the performance of your program, dScope must know when each code block you want to analyze is entered and exited. dScope must know how long it takes to execute each line so that it can calculate performance statistics.

Often, code blocks have multiple entrance points and exit points. This means that the only way to be certain that you have accurate timing data is to analyze each instruction to see if it belongs to a defined code range. This means that dScope must single-step through your entire target program. This causes target debugging to be very slow since communication with the PC is required for single-stepping. How slow really depends on the COM speed, but at 9600 baud, 1 second of real-time execution takes about 83 minutes of single-stepping.

Last Reviewed: Saturday, May 08, 2004