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Viewing profile — marshallward

marshallward

HN member
Joined
Mon, Oct 19, 2015, 12:41 AM UTC
HN karma
111
Public activity
45 items

About marshallward

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Recent public activity

  1. comment
    Comment #41260032

    > I hope you can list all of the groups of order Welp, guess I'm out.

  2. comment
    Comment #40587337

    Here is more recent video that beats those records: https://www.youtube.com/watch?v=jPyf5kIGoKA Except! Even this is now out of date, and I think BlueScuti has broken some of these…

  3. comment
    Comment #40382735

    > “The pyramids seem like pretty monumental work” You don't say...

  4. comment
    Comment #39947164

    I ran with OMP_NUM_THREADS=1, but your point is well taken. As for the original post, I felt a bit embarrassed about my original comments, but I think the compilers actually did fa…

  5. comment
    Comment #39901979

    I'm sure there's more to it, but just comparing the profile output shows aggressive use of prefetch and broadcast instructions.

  6. comment
    Comment #39900056

    I just did a test of OpenBLAS with Intel-compiled BLAS, and it was about 6 GFLOP/s vs 150 GFLOP/s, so I must admit that I was wrong here. Maybe in some sense 4% is not bad, but it'…

  7. comment
    Comment #39899901

    You are right, I just tested this out and my speed from BLAS to OpenBLAS went from 6 GFLOP/s to 150 GFLOP/s. I can only imagine what BLIS and MKL would give. I apologize for my ign…

  8. comment
    Comment #39896823

    I don't disagree, but where are those techniques presented in the article? It seems like she exploits the particular shape of her matrix to align better with cache. No BLAS library…

  9. comment
    Comment #39895144

    How do you feel about Nvidia endorsing do concurrent migration to GPUs? Would that be classified as parallelization?

  10. comment
    Comment #39895125

    Fair enough, this is not meant to be some endorsement of the standard Fortran BLAS implementations over the optimized versions cited above. Only that the mainstream compilers cited…

  11. comment
    Comment #39894316

    There is an implication here that the Fortran implementation of `SGEMM` is somehow inadequate. But any modern Fortran compiler will quite easily apply the AVX and FMA optimizations…

  12. comment
    Comment #38384657

    Unfortunately I don't think the compilers will add it in time.

  13. comment
    Comment #38282246

    I have only looked at the GCC Fortran frontend. I would not say it is necessarily difficult but rather very ad-hoc and disconnected from the rest of gcc. I don't see many tools for…

  14. comment
    Comment #37396165

    I know someone who took that course. They did not have fond memories of it. My impression is that it can be a very frustrating way to learn mechanics if you don't have much interes…

  15. comment
    Comment #37344414

    It's an excellent essay, and the Fortran community owes you a major gratitude for promoting these issues. But surely there loops can be safely parallelized if the iterations do not…

  16. comment
    Comment #37335425

    Very true, and it opens the door to new optimizations which are not possible when going through a library (at least in the case of MPI).

  17. comment
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  19. comment
    Comment #37331239

    I agree that it is not a parallel construct. But it can nonetheless be parallelized if certain criteria are met.

  20. comment
    Comment #37293152

    Do concurrent loops can also be parallelized.

  21. comment
    Comment #36787111

    I remember going to jai alai games in Miami as a kid. I was never very into sports, but it was fun to watch. As far as I could tell, the adults were there to bet on the games.

  22. comment
    Comment #36380511

    What is it about?

  23. comment
    Comment #35843304

    I have not yet seen anything like this, but I have observed the Intel compiler produce different bytecode on Intel and AMD machines. In one case, the compiler would use masking vec…

  24. comment
    Comment #34375532

    We work hard to retain floating point reproducibility in climate models. I have a presentation on this, if anyone is interested. https://www.marshallward.org/fortrancon2021/#/title…

  25. comment
    Comment #34212211

    True but every kind is considered a type.