-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/08/15 22:57, Justin Chang wrote:
Hi all,
Is it possible to include manual/PETSc counts within the assembly of the FormResidual and FormJacobian routines? Because I think it would be nice to look at the performance of how firedrake is assembling these finite element discretization instead of always relying on hardware counters.
Hi Justin, this is a good idea. The question is how to provide the information to PETSc. We know how many times we execute an element-wise Kernel (because we know how big the mesh is). So calculating the number of flops comes down to estimating the number of flops for a kernel. I have added some code to do this in the log-flops branches of COFFEE and PyOP2. It seems to report reasonably sensible numbers (I haven't compared with hardware counters). Hopefully these will merge soon. I use the same flop-counting approach as petsc, i.e. "effective double precision flops", where each multiplication, division, addition or subtraction counts as a single flop. The approach is not perfect, because I do not do this manually, so I'm currently assuming that any function call I see in the code contributes zero flops. This means that I'm underestimating a little, since the (affine) Jacobian computations are not counted. However, it gives you a reasonable estimate, and is better than laboriously counting by hand. If you really want to count the flops by hand, we can have a look at an example kernel. Cheers, Lawrence -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVwe+xAAoJECOc1kQ8PEYv5aMIALlx+GPD3C51n81OUE8l8xuN pAsT0tsBuditE//UIqqavDkOP92zn8GyQG5IVW5DNeMHY0x6a9wECEqxl4Otc8L1 6WuFXtuVg1g8UgKmsFzEuNH2/6VBPo7flGixe1be2sS+qFvpDKFnwJiKoUDAMjDa Re5tfGBfo/DXrK4rv0enRRLlD0quzQO1PJBt8BmkyZmEL4jdBMdOKTRCRmSO3kTV teNg/l30/SUhw8VV5VedW4wQop6QtK2XV6F/m1cYXTeXVPNAXHSAxmbG0zyj+LTI 3eP/96ISPRq6ctDMAKBHNNauiigCgeiuK+DBptR05lMPHx/cESO3tQPJuWE8o5c= =COjj -----END PGP SIGNATURE-----