Re: [Caml-list] an OCaml program profile

[John Whitington <john@coherentgraphics.co.uk>]

Hi,

Francois Berenger wrote:
> Hello,
>
> I am running experiments with a program.
> I'd like the program to run faster because
> it would reduce experiments round-trip.
>
> Here is the top of the profile:
> ---
> Flat profile:
>
> Each sample counts as 0.01 seconds.
> % cumulative self self total
> time seconds seconds calls s/call s/call name
> 58.07 132.13 132.13 161527987 0.00 0.00 caml_fl_allocate
> 21.13 180.21 48.08 2339 0.02 0.02 caml_fl_add_blocks
> 4.87 191.30 11.09 5497 0.00 0.00 mark_slice
> 1.65 195.06 3.76 979591485 0.00 0.00 caml_page_table_lookup
> 1.50 198.47 3.41 5620 0.00 0.00 sweep_slice
> 1.20 201.21 2.74 186584504 0.00 0.00 caml_oldify_one
> 1.04 203.57 2.36 134849325 0.00 0.00 compare_val
> 1.02 205.89 2.32 290049921 0.00 0.00 caml_float_compare
> 0.80 207.71 1.82 123048730 0.00 0.00 caml_hash
> 0.76 209.44 1.73 161525648 0.00 0.00 caml_alloc_shr
> ---
>
> I think the program spends most of its time doing garbage
> collection.
>
> How can I make it go faster?

Look further down the profile in the individual numbered sections for 
each function. The section for "caml_call_gc" usually provides the most 
useful start.

For example, if most calls to caml_call_gc are from List.rev, look at 
calls to that etc. It's not entirely straightforward, but after a bit of 
following numbers around the file, you'll get used to it.

Thanks,

-- 
John Whitington
Director, Coherent Graphics Ltd
http://www.coherentpdf.com/