[mvapich-discuss] wrapping calls to polling functions in MVAPICH2

[Jeff Hammond]

polling and profiling are different things.  your example is for
profiling and PMPI is the right way to do that.  you should avoid
reinventing the wheel and look at mpiP, TAU, etc. though.

if you want to implement asynchrony via polling, then it would help if
you gave a clear example of what you want in that respect.

jeff

On Mon, Aug 12, 2013 at 2:36 PM, Alexander Breslow <abreslow at cs.ucsd.edu> wrote:
> Hi,
>
> I was wondering if there is a single low-level function within MVAPICH2 that
> implements the polling functionality.  I have seen that polling is
> adjustable via the MV2 CM SPIN COUNT environment variable.  My goal is to be
> able to time all spinning explicitly.
>
> If this spinning is implemented by a call to a single function F, I would
> like to intercept all calls to that function, and redirect those calls to
> another function G that times the duration of each invocation of F.
>
> G would be something like the following:
>
> G(args){
>
> t1 = get_time_ns();
> F(args);
> t2 = get_time_ns();
> register(t2,t1);  // Enqueue for post processing
>
> }
>
> This seems feasible via the PMPI interface or by writing a library that uses
> DYLD functionality if the spinning/polling function appears in the symbol
> table of the respective MVAPICH2 object files.  If this is not possible,
> could you please tell me which source files that I would have to modify in
> order to achieve what I desire?
>
> Thanks in advance for your time,
> Alex
>
>
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-- 
Jeff Hammond
jeff.science at gmail.com