Done in branch barry/remove-papi
> On Oct 10, 2016, at 7:30 PM, Jed Brown <[email protected]> wrote:
>
> Barry Smith <[email protected]> writes:
>
>>> On Oct 10, 2016, at 7:09 PM, Jed Brown <[email protected]> wrote:
>>>
>>> Barry Smith <[email protected]> writes:
>>>
>>>> Funny, I thought Jed said I stripped out all the PAPI stuff? Maybe I
>>>> should really strip it out, has not been used in years and as Jed
>>>> says it has Jack's slimeprints on it.
>>>
>>> I haven't touched it.
>>
>> I know you didn't touch it. You said I (meaning Barry) stripped it out.
>
> I blame it on memory loss in my old age.
>
>>> Looks like you added it in 2009. I think we had
>>> a mailing list thread on it around that time.
>>>
>>> Counting flops with hardware counters is really error-prone on current
>>> hardware. I don't think we should ever trust it for linear algebra. It
>>> would perhaps be handy for people implementing their physics and
>>> discretizations, but the numbers may vary widely based on compiler/flag
>>> choices.
>>
>> Independent of its reliability, I found the way of managing what was
>> reported through its API in 2009 was very cumbersome and thus just left what
>> little I had done in place and never pursued it.
>>
>> As I said in my other email I'm fine with PETSc's current logging that
>> gives one the "big picture" of what is taking time and what is doing well
>> and poorly and think one can just use external tools like vtune for focused
>> studies on kernels people are interested in. I got some push back from
>> others in follow up email; but didn't see any rational for the push back
>> besides "it would be nice if we had more logging..." :-( I think people may
>> underestimate the amount of work and maintenance needed for PETSc to
>> properly manage more logging then we already do (there is already more lines
>> of convoluted logging code then I would ideally like to have).
>
> I'm fine with actually removing it. Advanced profiling is indeed a very
> complicated task.
