4.3 Simulator Output

Statistics on each function are collected during the simulation. These statistics include:

Number of calls

The number of times the function has been called.

Accumulated interpreted time

The total amount of time, over all calls, spent interpreting the function.

Accumulated native time

The total amount of time, over all calls, spent running the native code for the function.

In addition, statistics on the entire program are gathered. This includes:

• total execution time,
• time spent interpreting source code,
• time spent executing translated (non-library) code,
• time spent executing library routines, and
• time spent translating source code to native code.

As mentioned earlier, we are assuming that the Interpreter and Compiler modules are physically running in parallel, so the total execution time reported does not include the time spent translating. However, the total time for a single-processor system can be calculated by simply summing the total execution time and the translation time, and adding in some additional amount to account for the overhead of context switching.

In addition to the above, the following information about source files can be output:

• sorted list (in descending order) based on the total number of calls to all functions defined in the file,
• sorted list (in descending order) based on the total execution time of all functions defined in the file, where the total execution time for a function is calculated without the interpretation penalty, and
• the point in time that the Compiler module completes translation of each file.

The sorted lists are useful for implementing the most-frequently-executed-overall and longest-overall strategies. The lists can be used to specify the compilation order for subsequent runs of the simulator with the same setup and behavior files.