biographical profiling is broken?

[Ömer Sinan Ağacan]

Hi all,

I'm trying to use LDV profiling features of GHC but I'm failing.
Here's what I try:

(I'm using GHC 7.8.2)

* I'm compiling my app with `-prof` and I'm also using `-fprof-auto`
just to be sure.
* I'm running my app using `+RTS -hbdrag,void` as described in the
docs. (https://www.haskell.org/ghc/docs/latest/html/users_guide/prof-heap.html#biography-prof)

This always generates an empty MyApp.hp file. There's only this header
in the generated file:

  JOB "MyApp +RTS -hd -hbdrag,void,lag"
  DATE "Thu Aug  7 18:14 2014"
  SAMPLE_UNIT "seconds"
  VALUE_UNIT "bytes"
  BEGIN_SAMPLE 0.00
  END_SAMPLE 0.00
  BEGIN_SAMPLE 0.10
  END_SAMPLE 0.10

I tried different programs, from "hello world" to a complex language
interpreter. I always get the same file with only a header.

* I also tried adding more arguments like `-hc`, `-hm`, `-hr` etc. but
I got same results.

I feel like the feature is broken. I checked the test suite to find
some working LDV profiling programs. But as far as I can see we don't
have any tests for LDV stuff. There's a `bio001.stdout` which I
believe is related with "biographical profiling"(which means LDV) but
again AFAICS it's not used.

(I'm not having any different behaviors or exceptions while running
programs using LDV RTS arguments.)

Can anyone help me with this? Is anyone using this feature? Am I right
that this feature is not tested?

Thanks.

---
Ömer Sinan Ağacan
http://osa1.net