[Haskell-cafe] safe lazy IO or Iteratee?

[John Millikin]

Benchmark attached. It just enumerates a list until EOF is reached.

An interesting thing I've noticed is that IterateeMCPS performs better
with no optimization, but -O2 gives IterateeM the advantage. Their
relative performance depends heavily on the chunk size -- for example,
CPS is much faster at chunk size 1, but slower with 100-element
chunks.

On Fri, Feb 5, 2010 at 08:56, John Lato <jwlato at gmail.com> wrote:
> On Fri, Feb 5, 2010 at 4:31 PM, Valery V. Vorotyntsev
> <valery.vv at gmail.com> wrote:
>>> John Lato <jwlato at gmail.com> wrote:
>>>
>>>> Both designs appear to offer similar performance in aggregate,
>>>> although there are differences for particular functions.  I haven't
>>>> yet had a chance to test the performance of the CPS variant, although
>>>> Oleg has indicated he expects it will be higher.
>>
>> @jwlato:
>> Do you mind creating `IterateeCPS' tree in
>> <http://inmachina.net/~jwlato/haskell/iteratee/src/Data/>, so we can
>> start writing CPS performance testing code?
>
> I'm working on the CPS version and will make it public when it's done.
>  It may take a week or so; this term started at 90 and has picked up.
> I have several benchmark sources that aren't public yet, but I can put
> them online for your perusal.
>
>>
>> AFAICS, you have benchmarks for IterateeM-driven code already:
>> http://inmachina.net/~jwlato/haskell/iteratee/tests/benchmarks.hs
>
> Those will make more sense when I've added the context of the
> codebases in use.  There are several more sets of output that I simply
> haven't published yet, including bytestring-based variants.
>
>>
>> John Millikin <jmillikin at gmail.com> wrote:
>>
>>> I wrote some criterion benchmarks for IterateeM vs IterateeCPS, and
>>> the CPS version was notably slower. I don't understand enough about
>>> CPS to diagnose why, but the additional runtime was present in even
>>> simple cases (reading from a file, writing back out).
>
> That's very interesting.  I wonder if I'll see the same, and if I'd be
> able to figure it out myself...
>
> Did you benchmark any cases without doing IO?  Sometimes the cost of
> the IO can overwhelm any other measurable differences, and also disk
> caching can affect results.  Criterion should highlight any major
> outliers, but I still like to avoid IO when benchmarking unless
> strictly necessary.
>
>>
>> @jmillikin:
>> Could you please publish those benchmarks?
>
> +1
>
> John
>
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