Computer Architecture Group U.S.C. PPC: Performance prediction for selected application kernels Task 2.3.2 Computer Architecture Group U.S.C.

Introduction The global purpose of the tool is to provide performance information about some important computational MPI kernels when they are executed in a Grid. Two main works: To establish analytical models for: Basic simple kernels. Kernels from applications. A friendly to use Java GUI integrated in the M.D.

Establishing the models Monitoring information is needed X# monitoring not yet available for our needs Latency, bandwidth between any pair of nodes at any time In this meeting, we have contacted to Task 3.3 to adapt X# monitoring system to our needs More collaboration with Task 2.3 (GridBench) started to solve common problems NWS: installed in some sites as a temporary solution NWS allows us to sensor monitoring information between sites and also inside of them. Configurable to obtain data in any moment to know the current status of the Grid.

Establishing the models To take measures of execution time for the kernel: K measurements, Tk. At the same time, to get instant information from monitoring: M monitoring tests Measures of latency, Li, and bandwidth, Wi. We define a test cube in a three-dimensional space {L, W, T} This test cube is limited by the maximum and the minimum values of these parameters.

Establishing the models Monitoring measures must show enough homogeneity for the correlation search. In each test cube The meant point Representative value The size of the cube Dispersion of the data

Establishing the models Tests with different monitoring conditions and different kernel situations (size of the problem, etc.) determine several cube of tests. To obtain the correlation To establish the models

Analytical models for kernels Vertlq (from Task 1.4, air pollution task) Communications: is done Computations: is in progress Code was modified in order to use the size of the problem as a input parameter To take measurements for different scenarios PETSc (from Task 1.2, to solve linear systems) Communications and computations: characterized for same cases. Generalization is in progress.

Current status and future work We use NWS monitoring system, as a temporary solution, to obtain the analytical models. To try to use a X# monitoring system. We have models of some kernels in homogeneous systems. We are adding more functionalities to the GUI. We are completing models for some application kernels: Vertlq, PETSc, ... When done, to include them in the GUI.