1. EGEE-III INFSO-RI-222667 Enabling Grids for E-sciencE www.eu-egee.org EGEE and gLite are registered trademarks Modeling Grid Job Time Properties Lovro Ilijašić Lorenza Saitta University of Eastern Piedmont, Italy

2. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Modeling Grid Job Time Properties 2 Grid Observatory The Grid Observatory cluster of EGEE – the scientific view Data collection, analysis of behaviour and usage 20 months of data, more than 28 million jobs Development of models Grid is more than just a sum of its parts

3. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Emergent Behaviour Properties that are apparent only on higher levels of organization and are not present on the lower ones Emergent Behaviour is observable on all levels of reality Modeling Grid Job Time Properties 3

4. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Power Law Pareto distribution Zipfs law 80-20 rule Self similarity Modeling Grid Job Time Properties 4

5. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Degree Distributions In- and out-degree distributions: How users connect (use) CEs Weighted degrees: Distribution of number of jobs Modeling Grid Job Time Properties 5

6. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Job Lifecycle Analysis Modeling Grid Job Time Properties 6

7. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Distributions of Job Lengths Modeling Grid Job Time Properties 7

8. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Distributions in log-log scale Modeling Grid Job Time Properties 8

9. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Power-law vs. Log-normal Power-law: preferential attachment Power-law: optimization of the average amount of information per unit transmission cost Power-law: monkeys typing randomly Probabilities of letters not equal: power-law or log- normal? Modeling Grid Job Time Properties 9

10. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Log-normal vs. Power-law Log-normal: multiplicative processes At each step, the event (X t ) may grow or shrink, according to a random variable F t : X t = F t X t-1 Multiplicative models can also generate Pareto distribution if there is not a minimum size of event. Otherwise it is log-normal Intermixing of generations, where t is random variable, leads to power law. Modeling Grid Job Time Properties 10

11. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Log-normal Fitted Distributions Modeling Grid Job Time Properties 11

12. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Alternatives Double Pareto distribution Double Pareto log-normal distribution More distribution parameters that allow better fitting Modeling Grid Job Time Properties 12

13. EGEE-III INFSO-RI-222667 Enabling Grids for E-sciencE www.eu-egee.org EGEE and gLite are registered trademarks Modeling Grid Job Time Properties Lovro Ilijašić Lorenza Saitta University of Eastern Piedmont, Italy

14. Modeling Grid Job Time Properties 14

15. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Complex Networks Complex Networks – Complex systems represented as graphs Gathered experiences from Physics, Chemistry, Biology, Computer Science, Sociology, Economics… Representing Grid as a Complex Network 20 months of log data, more than 28 million jobs Edges representing jobs go from Users to CEs Modeling Grid Job Time Properties 15

16. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Number of jobs for each user Modeling Grid Job Time Properties 16

17. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Modeling Grid Job Time Properties 17

18. Enabling Grids for E-sciencE EGEE-III INFSO-RI-222667 Modeling Grid Job Time Properties 18