[MPICH2-dev] implementing MPID_Wtick()

[David Gingold]

Here is a question about implementing MPID_Wtick() in MPICH2:

We're presently using gettimeofday() on our system to implement  
MPI_Wtime().  As far as I know, there is no way to ask Linux what the  
resolution of gettimeofday() is, but I happen to know the answer in  
our case: 1 microsecond.  The "generic" implementation of MPID_Wtick 
() tries to determine this, but now and then it returns different  
values for different ranks.

To solve this, I'm inclined to add a parameter to configure.in that  
lets me specify, at build time, the value that MPI_Wtick() should  
return.  Is there a better way?  Is it expected, for example, that an  
ADI3 implementation might provide its own versions of the functions  
in src/mpid/timer/mpidtime.c, replacing or overriding what is there?

-dg

--
David Gingold
Principal Software Engineer
SiCortex
Three Clock Tower Place, Suite 210
Maynard MA 01754
(978) 897-0214 x224



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