xprofiler shows heavy communication

IBM has a variant of the gprof tool called xprofiler. If you link your program with -g and with -pg, the usual gmon.out files will be generated. These can be viewed with xprofiler, a GUI. Here, for example, we see the call tree of a large program, reconstructed from the gmon.out files:

[xprofiler.gif]

If you click on a routine with the right mouse button, you have a selection of information you can see about that routine, including an annotated source listing. Here is a portion of an annotated program source, showing the "do 12225" loop which contains many tick marks. 

   Line         Ticks      
   ----         -----
    135            2            do 12225 j = 1, ndemm
    136                           demand(j) = 0.
    137                           do 12230 k = 1, nsupm
    138            2                test =(-supp(k) - thxlin(k, j))*(1. + tar(k, j)) + demp(j)
    139            1                apath = apatho(k, j) + rho * test
    140           28                if (apath .lt. 0.) apath = 0.
    141           38                if (abs(apath- apatho(k,j)) .le. .01) iict = iict+1
    142                             apatho(k, j) = apath
    143           33                supply(k) = supply(k) + apath
    144                             demand(j) = demand(j) + apath
    145                 12230     continue
    146                 12225   continue
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