Re: [Caml-list] Optimizing pure-functional streams

[Yotam Barnoy <yotambarnoy@gmail.com>]

> I've played a little bit with different optimization options in flambda 4.04, and finally, all three versions of the loop: curried, uncurried, and the for-loop, have the same performance, though they still loose about 30% to the C version, due to tagging.

Would it perhaps make sense to try Int64 in order to avoid the tagging?

Also, I believe it would make sense to have Flambda try to switch to
an untagged type in tight loops to avoid this tagging cost.

On Tue, Jul 11, 2017 at 1:37 PM, Ivan Gotovchits <ivg@ieee.org> wrote:
> TWIMC,
>
> I've played a little bit with different optimization options in flambda
> 4.04, and finally, all three versions of the loop: curried, uncurried, and
> the for-loop, have the same performance, though they still loose about 30%
> to the C version, due to tagging.
>
> Basically, this means, that flambda was able to get rid of the allocation. I
> don't actually know which of the options finally made the difference, but
> this is how I compiled it.
>
> ocamlopt.opt -c -S -inlining-report -unbox-closures -O3 -rounds 8
> -inline-max-depth 256 -inline-max-unroll 1024 -o loop.cmx loop.ml
> ocamlopt.opt loop.cmx -o loop.native
>
>
> Regards,
> Ivan
>
>
>
>
> On Tue, Jul 11, 2017 at 8:54 AM, Simon Cruanes <simon.cruanes.2007@m4x.org>
> wrote:
>>
>> Hello,
>>
>> Iterators in OCaml have been the topic of many discussions. Another
>> option for fast iterators is https://github.com/c-cube/sequence ,
>> which (with flambda) should compile down to loops and tests on this kind
>> of benchmark. With the attached additional file on 4.04.0+flambda,
>> I obtain the following (where sequence is test-seq):
>>
>> $ for i in test-* ; do echo $i ; time ./$i ; done
>> test-c_loop
>> 5000000100000000
>> ./$i  0.08s user 0.00s system 97% cpu 0.085 total
>> test-f_loop
>> 5000000100000000
>> ./$i  0.10s user 0.00s system 96% cpu 0.100 total
>> test-loop
>> 5000000100000000
>> ./$i  0.18s user 0.00s system 97% cpu 0.184 total
>> test-seq
>> 5000000100000000
>> ./$i  0.11s user 0.00s system 97% cpu 0.113 total
>> test-stream
>> 5000000100000000
>> ./$i  0.44s user 0.00s system 98% cpu 0.449 total
>>
>>
>> Note that sequence is imperative underneath, but can be safely used as a
>> functional structure.
>>
>> --
>> Simon Cruanes
>>
>> http://weusepgp.info/
>> key 49AA62B6, fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA
>> 62B6
>
>