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Debugger Performance Considerations

A distributed file system makes it possible to develop your applications in a cross-development environment. In a distributed file system, programs can read or write files directly in a file system on a remote machine. The Network File System (NFS) client support that is provided by the SAS/C Connectivity Support Library enables the SAS/C Debugger to access files that do not reside on the mainframe at all. Additional information can be found in Using the NFS Client.

The main performance issue to consider when you debug in a cross-development environment is time. A debugger that runs on the mainframe can use a considerable amount of time to access files that reside on the host workstation. In general, you can improve performance by reducing the number of workstation files that are accessed by the debugger.

One method of improving debugger performance is to use the set search command in order to direct the debugger to mainframe files. For example, when you develop in a cross-development environment, it is likely that identical copies of the system-include files reside on both the host workstation and the target mainframe. Use the set search systeminclude command in order to direct the debugger to the system-include files that are located on the target mainframe.

Another way to improve performance is to specify a debugger Source Window buffer that is large enough to hold the entire source file. This allows the debugger to keep the entire source file in mainframe memory for the time that the compilation is being debugged. Switching compilations causes the file to be flushed. As a guideline, the amount of memory that is needed to hold one source line is equal to the length of the line, after stripping trailing blanks, plus three bytes. For more information about debugger window buffers, see Config Window. For information about the window memory command, see window.

It may be advantageous to use a file transfer mechanism, such as FTP, to copy some of the source, include, and debugger files to the target mainframe. For example, your system may not have a distributed file system, or your situation may require you to minimize network traffic. In addition, if you are debugging an application that is composed of many source files and you are only actively developing the code in one or two of those files, the performance of the debugger improves if the inactive source files reside on the target mainframe as well as the host workstation.

Similarly, you may use the set cache command in order to establish a cache location for your debugger file.

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