2018-07-02 11:48 GMT+03:00 Vaclav Hapla <vaclav.ha...@erdw.ethz.ch>: > Barry wrote: > > This could get ugly real fast, for example, for vector operations, there > may be dozens of named vectors and each one gets its own logging? You'd > have to make sure that only the objects you care about get named, is that > possible? > > I don't know if there is a good solution within the PETSc logging > infrastructure to get what you want but maybe what you propose is the best > possible. > > > As I suggest, this behavior would be only triggered by a specific option. > > I think there are actually 4 strings which could be used as an event name > suffix in log view: > 1) name > 2) prefix > 3) type > 4) custom string (set by something like PetscObjectSetLogViewSuffix) > I think the best would be to let user choose by offering > -log_view_by_{name,prefix,type,suffix}. > > For example, with -log_view_by_prefix, you could readily distinguish > PCTelescope outer and inner apply, because you would see a separate > "PCApply (telescope_)" event. > With -log_view_by_type, you would see PCApply (telescope). > > I think this would be useful because the current class-wide events like > MatMult or PCApply aggregate very different operations from which some are > for free and some form hotspots. > > > Stefano wrote: > > The issue with this sort of “dynamic” logging is that now PETSc requires > PetscLogEvent created during the registration of the class, so that all the > ranks in PETSC_COMM_WORLD have the same events registered. > What you propose is not generally supported for this specific reason. > > Your “log_name” may work if users register their own classes (with their > own LogEvents created properly), and currently we don’t have support (maybe > I’m wrong) to add an “InitializePackage” method for the users’ registered > classes. > > > I don't agree. What I suggest is basically an ability to allow > automatically created object-wise events, so it _can't_ be managed during > the class registration. In presence of respective option, the event would > be created during PetscLogEventBegin by taking the class-wide event's name, > concatenating the suffix and registering a new event. The event id would be > stored in the PetscObject structure. > > As I said before, now PETSc event model assumes the events are created at class registration. I'm not saying your dynamic thing cannot be done; I'm saying it will likely deadlock
> > Matt wrote: > > As people have pointed out, this would not work well for Events. However, > this is exactly what stages are for. > Use separate stages for the different types of MatMult. I did this, for > example, when looking at performance > on different MG levels. > > > Yes, performance on different MG levels is a nice use case. I don't > understand how you inject stages into MatMults. To me it's exactly the same > problem as with events - you have to define MatMult_custom where you take > the original mult and wrap into PetscStageLogPush/Pop and then use > MatSetOperation to redefine MatMult. Or do you mean something more elegant? > > Thanks > > Vaclav > > > > 29. 6. 2018 v 22:42, Smith, Barry F. <bsm...@mcs.anl.gov>: > > > > On Jun 29, 2018, at 9:33 AM, Vaclav Hapla <vaclav.ha...@erdw.ethz.ch> > wrote: > > > > 22. 6. 2018 v 17:47, Smith, Barry F. <bsm...@mcs.anl.gov>: > > > > On Jun 22, 2018, at 5:43 AM, Pierre Jolivet <pierre.joli...@enseeiht.fr> > wrote: > > Hello, > I’m solving a system using a MATSHELL and PCGAMG. > The MPIAIJ Mat I’m giving to GAMG has a specific structure (inherited from > the MATSHELL) I’d like to exploit during the solution phase when the > smoother on the finest level is doing MatMults. > > Is there some way to: > 1) decouple in -log_view the time spent in the MATSHELL MatMult and in the > smoothers MatMult > > > You can register a new event and then inside your MATSHELL MatMult() call > PetscLogEventBegin/End on your new event. > > Note that the MatMult() like will still contain the time for your > MatShell mult so you will need to subtract it off to get the time for your > non-shell matmults. > > > In PERMON, we sometimes have quite complicated hierarchy of wrapped > matrices and want to measure MatMult{,Transpose,Add,TransposeAdd} > separately for particular ones. Think e.g. of having additive MATCOMPOSITE > wrapping multiplicative MATCOMPOSITE wrapping MATTRANSPOSE wrapping MATAIJ. > You want to measure this MATAIJ instance's MatMult separately but you > surely don't want to rewrite implementation of MatMult_Transpose or force > yourself to use MATSHELL just to hang the events on MatMult*. > > We had a special wrapper type just adding some prefix to the events for > the given object but this is not nice. What about adding a functionality to > PetscLogEventBegin/End that would distinguish based on the first > PetscObject's name or option prefix? Of course optionally not to break guys > relying on current behavior - e.g. under something like -log_view_by_name. > To me it's quite an elegant solution working for any PetscObject and any > event. > > > This could get ugly real fast, for example, for vector operations, there > may be dozens of named vectors and each one gets its own logging? You'd > have to make sure that only the objects you care about get named, is that > possible? > > I don't know if there is a good solution within the PETSc logging > infrastructure to get what you want but maybe what you propose is the best > possible. > > Barry > > > I can do that if I get some upvotes. > > Vaclav > > > 2) hardwire a specific MatMult implementation for the smoother on the > finest level > > > In the latest release you do MatSetOperation() to override the normal > matrix vector product with anything else you want. > > > Thanks in advance, > Pierre > > PS : here is what I have right now, > MatMult 118 1.0 1.0740e+02 1.6 1.04e+13 1.6 1.7e+06 6.1e+05 > 0.0e+00 47100 90 98 0 47100 90 98 0 81953703 > […] > PCSetUp 2 1.0 8.6513e+00 1.0 1.01e+09 1.7 2.6e+05 4.0e+05 > 1.8e+02 5 0 14 10 66 5 0 14 10 68 94598 > PCApply 14 1.0 8.0373e+01 1.1 9.06e+12 1.6 1.3e+06 6.0e+05 > 2.1e+01 45 87 72 78 8 45 87 72 78 8 95365211 // I’m guessing a lot of > time here is being wasted in doing inefficient MatMults on the finest level > but this is only speculation > > Same code with -pc_type none -ksp_max_it 13, > MatMult 14 1.0 1.2936e+01 1.7 1.35e+12 1.6 2.0e+05 6.1e+05 > 0.0e+00 15100 78 93 0 15100 78 93 0 88202079 > > The grid itself is rather simple (two levels, extremely aggressive > coarsening), > type is MULTIPLICATIVE, levels=2 cycles=v > KSP Object: (mg_coarse_) 1024 MPI processes > linear system matrix = precond matrix: > Mat Object: 1024 MPI processes > type: mpiaij > rows=775, cols=775 > total: nonzeros=1793, allocated nonzeros=1793 > > linear system matrix followed by preconditioner matrix: > Mat Object: 1024 MPI processes > type: shell > rows=1369307136, cols=1369307136 > Mat Object: 1024 MPI processes > type: mpiaij > rows=1369307136, cols=1369307136 > total: nonzeros=19896719360, allocated nonzeros=19896719360 > > > -- Stefano