The ITC/A timeline
- Before we can view the ITC instrumented trace, we'll need to compile and run the new code.
Exercise: Do this!
Switch to the ParallelPi_VT directory on a head node (bhX/ihX) and then compile the program.
[agopu@bh2 agopu]$ cd ~/MPI_Tutorial/ParallelPi_VT/ [agopu@bh2 ParallelPi_VT]$ make
Then run the ITC instrumented code on interactive nodes you got through qsub -I (bcXX/icXX)
[agopu@bc81 agopu]$ cd ~/MPI_Tutorial/ParallelPi_VT/ [agopu@bc81 ParallelPi_VT]$ lamboot $PBS_NODEFILE [agopu@bc81 ParallelPi_VT]$ mpirun C parallelPiVt 10000 [agopu@bc81 ParallelPi_VT]$ lamhalt
Finally, open the trace file, that's created, by doing:
[agopu@bc81 ParallelPi_VT]$ traceanalyzer parallelPiVt.stf
In the following figure the ITA timeline of the parallelPiVt program with the additional ITC instrumentation is shown:
Do you see the appearance of the states we titled for-loop and print thereby increasing the resolution of our analysis?? Probably not! Because the entire computation took very little time, in the order of milliseconds. The real guts of the computation are in the for-loop when the integral is calculated. Thus, you shouuld try increasing the number of steps from 10000 to, say, 1,000,000 and see how that changes the timeline, i.e. run the program as
Exercise: Do this!
[agopu@bc81 ParallelPi_VT]$ lamboot $PBS_NODEFILE [agopu@bc81 ParallelPi_VT]$ mpirun C parallelPiVt 1000000 [agopu@bc81 ParallelPi_VT]$ lamhalt
[agopu@bc81 ParallelPi_VT]$ traceanalyzer parallelPiVt.stf
- A sample detailed timeline if 200,000 is used as the number of steps, is shown below; it's obvious that with the increased number of steps, more time is spent in the computational part of the code (i.e. the for-loop) and our parallelization makes a bit more sense!
