[Users] counting number of bytes communicated in Carpet

[Erik Schnetter]

Roland

Thorn Carpet does not yet count communicated bytes; this feature was
never completed. However, thorn CarpetLib has timers that do count
communicated bytes:

There are two similar timing classes, one defined in Carpet/Timers's
"Timer.hh", the other in CarpetLib's "timestat.hh". Unfortunately,
both are called "Timer", although they live in different namespaces
(Timers and CarpetLib, respectively). This is a result of an
incomplete transition from timestat.hh to the Timers thorn. Only
timestat.hh counts bytes as well.

(Incidentally, I am currently transitioning to a third timing class
which is (a) thread-safe (thorn Timers isn't) and (b) uses C++
features instead of thorn CycleClock.)

To find out details, look at the routine "CarpetLib_printtimestats"
that outputs the timing statistics with the byte counts. This is
rather low-level output, and is not aggregated across processes. There
are a few CarpetLib parameters with "timestat" in their name that
control this. By default, these files are called
"carpetlib-timing-statistics".

These statistics contain actual byte counts, gathered next to the
actual MPI statements. Thorn Carpet might also produce higher-level
estimates based on numbers of grid functions, component sizes, numbers
of ghost zones etc.; these numbers would be less reliable.

-erik


On Tue, Feb 14, 2017 at 12:38 AM, Roland Haas <rhaas at illinois.edu> wrote:
> Hello Erik, all,
>
> is there a (simple?) way to output the total amount of data communicated
> in a run? I tried Carpet::timing and its comm_bytes_count however that
> one is only set in Carpet/src/Timing.c's EndTimingCommunication function
> which does not seem to be called anywhere anymore.
>
> Yours,
> Roland
>
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-- 
Erik Schnetter <schnetter at cct.lsu.edu>
http://www.perimeterinstitute.ca/personal/eschnetter/