7.12.2 Combining trace counts

The ‘mtc_union’ tool can be used to combine several trace count files into one trace count file. You need to use this when you have many trace count files you wish to analyse with ‘mslice’ or ‘mdice’.

‘mtc_union’ is invoked by issuing a command of the form:

mtc_union [-v] -o output_file file1 file2 …

‘file1’, ‘file2’, etc. are the trace count files that should be combined. The new trace count file will be written to ‘output_file’. This file will preserve the count of the test cases that contributed to its contents, even if some of ‘file1’, ‘file2’, etc themselves were created by ‘mtc_union’. If the ‘-v’ or ‘--verbose’ option is specified then a progress message will be displayed as each file is read and its contents merged into the union.

The ‘mtc_diff’ tool can be used to subtract one trace count file from another.

‘mtc_diff’ is invoked by issuing a command of the form:

mtc_diff -o output_file file1 file2

‘file1’ and ‘file2’ must both be trace counts files. The output, written to ‘output_file’, will contain the difference between the trace counts in ‘file1’ and ‘file2’ for every event that occurs in ‘file1’. Unlike ‘mtc_union’, ‘mtc_diff’ does not preserve the count of the test cases that contributed to its contents in any useful way.