Barry Smith <bsm...@mcs.anl.gov> writes: >> On Oct 10, 2016, at 7:09 PM, Jed Brown <j...@jedbrown.org> wrote: >> >> Barry Smith <bsm...@mcs.anl.gov> 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.
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