MLton 20210117

# MLmon

An mlmon.out file records dynamic profiling counts.

## File format

An mlmon.out file is a text file with a sequence of lines.

- The string "MLton prof".

- The string "alloc", "count", or "time", depending on the kind of profiling information, corresponding to the command-line argument supplied to mlton -profile.

- The string "current" or "stack" depending on whether profiling data was gathered for only the current function (the top of the stack) or for all functions on the stack. This corresponds to whether the executable was compiled with -profile-stack false or -profile-stack true.

- The magic number of the executable.

- The number of non-gc ticks, followed by a space, then the number of GC ticks.

- The number of (split) functions for which data is recorded.

- A line for each (split) function with counts. Each line contains an integer count of the number of ticks while the function was current. In addition, if stack data was gathered (-profile-stack true), then the line contains two additional tick counts:

  - the number of ticks while the function was on the stack.

  - the number of ticks while the function was on the stack and a GC was performed.

- The number of (master) functions for which data is recorded.

- A line for each (master) function with counts. The lines have the same format and meaning as with split-function counts.