Abstract: A diagnostic system in which, at every point in time, a forecast is made of the future response times of each EPP (End-to-end Probe Platform) probe in a battery of probes. Thresholds are established in terms of the distribution of future EPP values. The theory of Generalized Additive Models is used to build a predictive model based on a combination of a) data normally generated by network nodes, b) results of a battery of probes and c) profile curves reflecting expected response times (i.e. based on recent history) corresponding to this battery for various times of day, days of week, month of year, etc. The model is pre-computed, and does not have to be dynamically adjusted. The model produces, at regular intervals, forecasts for outcomes of various EPP probes for various horizons of interest; also, it produces thresholds for the respective forecasts based on a number of factors, including acceptable rate of false alarms, forecast variance and EPP values that are expected based on the recorded history.

Abstract: One embodiment of the present invention provides a system that facilitates modeling the effects of overlapping of memory references in a queueing system model. The system receives a memory reference during execution of a queueing system model. Upon receiving the memory reference, the system determines if the memory reference generates a cache miss. If so, the system models the cache miss in a manner that accounts for possible overlapping of the cache miss with other memory references and other processor operations.

Abstract: An apparatus and method for identifying clusters in two-dimensional data by generating a two-dimensional histogram characterized by a grid of bins, determining a density estimate based on the bins, and identifying at least one cluster in the data. A smoothed density estimate is generated using a Gaussian kernel estimator algorithm. Clusters are identified by locating peaks and valleys in the density estimate (e.g., by comparing slope of adjacent bins). Boundaries (e.g., polygons) around clusters are identified using bins after bins are identified as being associated with a cluster. Boundaries can be simplified (e.g., by reducing the number of vertices in a polygon) to facilitate data manipulation.

Abstract: A diagnostic system in which, at every point in time, a forecast is made of the future response times of each EPP (End-to-end Probe Platform) probe in a battery of probes. Thresholds are established in terms of the distribution of future EPP values. The theory of Generalized Additive Models is used to build a predictive model based on a combination of a) data normally generated by network nodes, b) results of a battery of probes and c) profile curves reflecting expected response times (i.e. based on recent history) corresponding to this battery for various times of day, days of week, month of year, etc. The model is pre-computed, and does not have to be dynamically adjusted. The model produces, at regular intervals, forecasts for outcomes of various EPP probes for various horizons of interest; also, it produces thresholds for the respective forecasts based on a number of factors, including acceptable rate of false alarms, forecast variance and EPP values that are expected based on the recorded history.

Abstract: One embodiment of the present invention provides a system that facilitates modeling the effects of overlapping of memory references in a queueing system model. The system receives a memory reference during execution of a queueing system model. Upon receiving the memory reference, the system determines if the memory reference generates a cache miss. If so, the system models the cache miss in a manner that accounts for possible overlapping of the cache miss with other memory references and other processor operations.

Abstract: A method for generating an uncertainty characterization for a system simulation model, including obtaining system simulation input for the system simulation model, generating a sensitivity characterization using the system simulation input, and generating the uncertainty characterization for the system simulation model using the sensitivity characterization.

Abstract: A method for generating an uncertainty characterization for a system simulation model, including obtaining system simulation input, wherein the system simulation input comprises a cache simulation output, generating one of the group consisting of a deterministic uncertainty model and a stochastic uncertainty model, using the cache simulation output and the system simulation model for at least one system input configuration, and generating the uncertainty characterization for the system simulation model using one of the group consisting of the deterministic uncertainty model and the stochastic uncertainty model.

Abstract: A method for a cache architecture simulation includes obtaining a first sample set for the cache architecture using a non-stationary Gaussian field model, performing a cache architecture simulation using the first sample set to produce a first set of simulation data, and fitting a first multivariate model to the first set of simulation data.

Abstract: A method for modeling a system configuration, including isotonizing an unconstrained additive model of a cache architecture to obtain an isotonic additive model for the cache architecture, wherein the isotonic additive model is of the same functional form as the unconstrained additive model, smoothing the isotonic additive model using a flat spot technique to obtain a characterization of the cache architecture, and modeling a system configuration using the characterization of the cache architecture.

Abstract: An apparatus and method for identifying clusters in two-dimensional data by generating a two-dimensional histogram characterized by a grid of bins, determining a density estimate based on the bins, and identifying at least one cluster in the data. A smoothed density estimate is generated using a Gaussian kernel estimator algorithm. Clusters are identified by locating peaks and valleys in the density estimate (e.g., by comparing slope of adjacent bins). Boundaries (e.g., polygons) around clusters are identified using bins after bins are identified as being associated with a cluster. Boundaries can be simplified (e.g., by reducing the number of vertices in a polygon) to facilitate data manipulation.