MLton 20051202 MLtonProfile
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signature MLTON_PROFILE =
   sig
      structure Data:
         sig
            type t

            val equals: t * t -> bool
            val free: t -> unit
            val malloc: unit -> t
            val write: t * string -> unit
         end

      val isOn: bool
      val withData: Data.t * (unit -> 'a) -> 'a
   end

MLton.Profile provides Profiling control from within the program, allowing you to profile individual portions of your program. With MLton.Profile, you can create many units of profiling data (essentially, mappings from functions to counts) during a run of a program, switch between them while the program is running, and output multiple mlmon.out files.

Example

Here is an example, taken from the examples/profiling directory, showing how to profile the executions of the fib and tak functions separately. Suppose that fib-tak.sml contains the following.

structure Profile = MLton.Profile
   
val fibData = Profile.Data.malloc ()
val takData = Profile.Data.malloc ()

fun wrap (f, d) x =
   Profile.withData (d, fn () => f x)

val rec fib =
   fn 0 => 0
    | 1 => 1
    | n => fib (n - 1) + fib (n - 2)
val fib = wrap (fib, fibData)

fun tak (x,y,z) =
   if not (y < x)
      then z
   else tak (tak (x - 1, y, z),
             tak (y - 1, z, x),
             tak (z - 1, x, y))
val tak = wrap (tak, takData)

val rec f =
   fn 0 => ()
    | n => (fib 38; f (n-1))
val _ = f 2

val rec g =
   fn 0 => ()
    | n => (tak (18,12,6); g (n-1))
val _ = g 500

fun done (data, file) =
   (Profile.Data.write (data, file)
    ; Profile.Data.free data)
    
val _ = done (fibData, "mlmon.fib.out")
val _ = done (takData, "mlmon.tak.out")

Compile and run the program.

% mlton -profile time fib-tak.sml
% ./fib-tak

Separately display the profiling data for fib

% mlprof fib-tak mlmon.fib.out
5.77 seconds of CPU time (0.00 seconds GC)
function   cur 
--------- -----
fib       96.9%
<unknown>  3.1%

and for tak

% mlprof fib-tak mlmon.tak.out
0.68 seconds of CPU time (0.00 seconds GC)
function  cur  
-------- ------
tak      100.0%

Combine the data for fib and tak by calling mlprof with multiple mlmon.out files.

% mlprof fib-tak mlmon.fib.out mlmon.tak.out mlmon.out
6.45 seconds of CPU time (0.00 seconds GC)
function   cur 
--------- -----
fib       86.7%
tak       10.5%
<unknown>  2.8%


Last edited on 2005-12-01 22:21:31 by StephenWeeks.