Dave,
You’re right, we screwed up (some #define not correctly set). I have a patch,
I’ll push it asap.
George.
> On Nov 19, 2014, at 05:19 , Dave Love wrote:
>
> "Daniels, Marcus G" writes:
>
>> On Mon, 2014-11-17 at 17:31 +, Dave Love wrote:
>>> I discovered from looking at the mpiP profiler that OMPI always uses
>>> gettimeofday rather than clock_gettime to implement mpi_wtime on
>>> GNU/Linux, and that looks sub-optimal.
>>
>> It can be very expensive in practice, especially for codes that have
>> fine-grained instrumentation.
>
> OK, but I assumed VT would take that sort of thing into account for
> platforms I don't have. clock_gettime(CLOCK_MONOTONIC,) is as fast as
> gettimeofday on our mainstream sort of system (RHEL6, sandybridge);
> CLOCK_MONOTONIC_COARSE is about three times faster. [I can't find that
> sort of information in Linux doc.]
>
> Perhaps there should be a choice via an MCA parameter, but it looks as
> though it should default to clock_gettime on x86_64 Linux. I suppose
> one can argue what "high resolution" means in the mpi_wtime doc, but I'd
> rather not.
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