Re: [Caml-list] an OCaml program profile

[Gabriel Scherer <gabriel.scherer@gmail.com>]

I have found the "poor man profiler" approach to work well when you
want to know not only which functions calls some slow runtime function
the most, but only in which situation (it depends on the callstack and
not only the source location). Ygrek's pmpa script is very helpful for
that
  http://ygrek.org.ua/p/code/pmpa


On Fri, Sep 6, 2013 at 10:28 AM, John Whitington
<john@coherentgraphics.co.uk> wrote:
> 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/
>
>
>
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