Scalasca  (Scalasca 2.6, revision 748ac9e9)
Scalable Performance Analysis of Large-Scale Applications
Initial summary measurement

The instrumented executable prepared in the previous step can now be executed under the control of the scalasca -analyze (or short scan) convenience command to perform an initial summary measurement:

  $ cd bin
  $ scalasca -analyze mpiexec -n 144 ./bt.D.144
  S=C=A=N: Scalasca 2.5 runtime summarization
  S=C=A=N: ./scorep_bt_144_sum experiment archive
  S=C=A=N: Mon Mar 18 13:44:46 2019: Collect start
  mpiexec -n 144 ./bt.D.144


   NAS Parallel Benchmarks 3.3 -- BT Benchmark

   No input file inputbt.data. Using compiled defaults
   Size:  408x 408x 408
   Iterations:  250    dt:   0.0000200
   Number of active processes:   144

   Time step    1
   Time step   20
   Time step   40
   Time step   60
   Time step   80
   Time step  100
   Time step  120
   Time step  140
   Time step  160
   Time step  180
   Time step  200
   Time step  220
   Time step  240
   Time step  250
   Verification being performed for class D
   accuracy setting for epsilon =  0.1000000000000E-07
   Comparison of RMS-norms of residual
             1 0.2533188551738E+05 0.2533188551738E+05 0.1499315900507E-12
             2 0.2346393716980E+04 0.2346393716980E+04 0.8546885387975E-13
             3 0.6294554366904E+04 0.6294554366904E+04 0.2745293523008E-14
             4 0.5352565376030E+04 0.5352565376030E+04 0.8376934357159E-13
             5 0.3905864038618E+05 0.3905864038618E+05 0.6650300273080E-13
   Comparison of RMS-norms of solution error
             1 0.3100009377557E+03 0.3100009377557E+03 0.1373406191445E-12
             2 0.2424086324913E+02 0.2424086324913E+02 0.1600422929406E-12
             3 0.7782212022645E+02 0.7782212022645E+02 0.4090394153928E-13
             4 0.6835623860116E+02 0.6835623860116E+02 0.3596566920650E-13
             5 0.6065737200368E+03 0.6065737200368E+03 0.2605201960010E-13
   Verification Successful


   BT Benchmark Completed.
   Class           =                        D
   Size            =            408x 408x 408
   Iterations      =                      250
   Time in seconds =                   413.25
   Total processes =                      144
   Compiled procs  =                      144
   Mop/s total     =                141162.75
   Mop/s/process   =                   980.30
   Operation type  =           floating point
   Verification    =               SUCCESSFUL
   Version         =                    3.3.1
   Compile date    =              18 Mar 2019

   Compile options:
      MPIF77       = scorep mpifort
      FLINK        = $(MPIF77)
      FMPI_LIB     = (none)
      FMPI_INC     = (none)
      FFLAGS       = -O2
      FLINKFLAGS   = -O2
      RAND         = (none)


   Please send feedbacks and/or the results of this run to:

   NPB Development Team
   Internet: npb@nas.nasa.gov


  S=C=A=N: Mon Mar 18 13:51:47 2019: Collect done (status=0) 421s
  S=C=A=N: ./scorep_bt_144_sum complete.

  $ ls scorep_bt_144_sum
  MANIFEST.md  profile.cubex  scorep.cfg  scorep.log

As can be seen, the measurement run successfully produced an experiment directory named scorep_bt_144_sum containing

However, application execution took almost twice as long as the reference run (413.25 vs. 216.00 seconds). That is, instrumentation and associated measurements introduced a non-negligible amount of run-time overhead. While it is possible to interactively examine the generated summary result file using the Cube report browser, this should only be done with great caution since the substantial overhead negatively impacts the accuracy of the measurement. Therefore, such measurements can easily be misleading.



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