1. Computation Time Analysis - Climate Reanalysis Data Dipanwita Dasgupta University of Notre Dame Graduate Operating Systems

2. Motivation Climate Analysis : Why it is important?  Increase in occurrence of climate hazards Climate Reanalysis Data  Data Centric Approach  Climate Network Slide 2

3. Dataset National Centre for Environemental Prediction / National Centre for Atmospheric Research (NCEP/NCAR) Reanalysis Dataset  Composed of data at 17 pressure levels  Total of approximately 10000 grid points  Factors affecting climate Slide 3

4. Background Climate Network Model  Limited to use 7 factors affecting climate  Affects the predictive modeling  Computation Time Slide 4 out of x

5. Problem Computation has 3 steps 1. Reading the data from file 2. Calculation at each level 3. Combining the results Step 2 – highly computation intensive The present code can only handle 20 units of data at a time Slide 5

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7. Actual Work Analyzed time taken to run on a single machine Distributed Framework  Steps 1 and 2 mentioned in previous slide for each level are independent of each other  Ran in a distributed fashion  Used the CRC SGE Machine Slide 7

8. Assumptions Used only one parameter – Geopotential Height Only one measure of dispersion – Euclidean Distance Processing is similar for other parameters as well as for measures of dispersion Slide 8

9. Experimental Set-up NCEP Reanalysis Dataset 20 units of longitude Sequential Execution  Used the school workstation desktop Distributed Framework  Used opteron.crc.nd.edu Slide 9

10. Distributed Framework: Setup opteron.crc.nd.edu Submitted Bash script Ran 10 simulations per level Took the average Slide 10

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13. Speedup Slide 13

14. Results Analysis Distributed Framework works better than Sequential Execution Expected Speed-Up not achieved  Reading data from the file took more time than expected  Reduced time for the other steps Slide 14

15. Future Work Optimization of reading data from file Use various file systems – NFS/AFS Include more measures of dispersion Increase the number of parameters Slide 15

16. Questions?? Slide 16