Re: [Caml-list] Sundials/ML 2.5.0

[Jun Inoue <jun.lambda@gmail.com>]

On Fri, Nov 28, 2014 at 10:05 PM, Jun Inoue <jun.lambda@gmail.com> wrote:
> Thank you for sharing this interesting information, Gabriel!  We
> benchmarked the code exclusively with 4.01.0 and didn't know about the
> performance boost in printf.
>
> I just measured the performance with
> examples/kinsol/serial/kinFerTron_dns.ml, which was one of the
> examples that had the most pronounced effect.  As you suggest, the
> numbers are a lot closer with 4.02.1.  The median wall-clock times of
> 10 runs were:
>
> printf,  OCaml 4.02.1: 1.76[s]
> print_*, OCaml 4.02.1: 1.62[s]
> printf,  OCaml 4.01.0: 2.04[s]
> print_*, OCaml 4.01.0: 1.70[s]
>
> The overhead of using printf is about 8% in 4.02.1, as opposed to
> about 20% in 4.01.0.  So in 4.02 the effect is noticeably smaller,
> though not unmeasurable.  We should note this in the doc in a future
> release.

Correction: the numbers are the medians of the ratios between OCaml
and C (wall-clock time).  The C version takes right about 1[s], so the
conclusion is morally the same, though.

>
> FYI, the experiment can be reproduced as follows (in bash syntax),
> using the attached patch (referred to as
> /tmp/kinFerTron_dns_printf.diff below):
>
> # Start at the root of the source tree.
> opam switch 4.02.1; eval `opam config env`
> ./configure && make clean all
> cd examples/kinsol/serial
> # Measure without modification.
> make PERF_DATA_POINTS=10 kinFerTron_dns.opt.perf
> ../../utils/crunchperf -m kinFerTron_dns.opt.perf >
> no-printf-4.02.1-kinFerTron_dns.opt.perf
> # Apply patch and measure again.
> patch -p4 < /tmp/kinFerTron_dns_printf.diff
> make PERF_DATA_POINTS=10 kinFerTron_dns.opt.perf
> ../../utils/crunchperf -m kinFerTron_dns.opt.perf >
> printf-4.02.1-kinFerTron_dns.opt.perf
> # Undo changes.
> patch -p4 -R < /tmp/kinFerTron_dns_printf.diff
>
> cd ../../..
> # Back at the root of the source tree.
> opam switch 4.01.0; eval `opam config env`
> # (Basically the same thing as above)
> ./configure && make clean all
> cd examples/kinsol/serial
> make PERF_DATA_POINTS=10 kinFerTron_dns.opt.perf
> ../../utils/crunchperf -m kinFerTron_dns.opt.perf >
> no-printf-4.01.0-kinFerTron_dns.opt.perf
> patch -p4 < /tmp/kinFerTron_dns_printf.diff
> make PERF_DATA_POINTS=10 kinFerTron_dns.opt.perf
> ../../utils/crunchperf -m kinFerTron_dns.opt.perf >
> printf-4.01.0-kinFerTron_dns.opt.perf
>
> # Summarize results
> for i in *kinFerTron_dns.opt.perf; do printf "\n[$i]\n";
> ../../utils/crunchperf -s $i; done
>
> On Fri, Nov 28, 2014 at 6:44 PM, Gabriel Scherer
> <gabriel.scherer@gmail.com> wrote:
>> Thanks for the significant effort put in documenting the bindings
>> (and, of course, the cool software and research); your "information
>> and documentation" page is impressive.
>>
>> The page has a very interesting performance comparison of numeric code
>> partly or fully written in OCaml (using bigarrays of floats) -- and
>> the not-so-surprising results is that the run times of the OCaml
>> programs are between 100% and 200% of the run time of the reference C
>> implementation.
>>
>> ( http://inria-parkas.github.io/sundialsml/perf.opt.png )
>>
>> I'm curious about this specific part of the explanation:
>>
>>> For instance, some OCaml versions spend a significant fraction of their time
>>> in printf, and we were able to lower their ratios by instead using print_string and print_int.
>>
>> The new 4.02 implementation of formats, due to Benoît Vaugon, should
>> be significantly faster (in my experience they match the performance of the
>> less-readable print_* sequence in most situations). Did you try those
>> OCaml versions with 4.02?
>>
>> On Fri, Nov 28, 2014 at 2:39 PM, Timothy Bourke <Timothy.Bourke@inria.fr> wrote:
>>> We are pleased to announce Sundials/ML, an OCaml interface to the
>>> Sundials suite of numerical solvers (CVODE, CVODES, IDA, IDAS, KINSOL).
>>>
>>> Information and documentation: http://inria-parkas.github.io/sundialsml/
>>> Source code (BSD):             https://github.com/inria-parkas/sundialsml
>>>
>>> opam install sundialsml # (requires Sundials 2.5.0)
>>>
>>> We gratefully acknowledge the original authors of Sundials, and the
>>> support of the ITEA 3 project 11004 MODRIO (Model driven physical
>>> systems operation), Inria, and the Departement d'Informatique de l'ENS.
>>>
>>> Timothy Bourke, Jun Inoue, and Marc Pouzet.
>>>
>
>
>
> --
> Jun Inoue



-- 
Jun Inoue