R: Timing SNOW Clusters

snow-timing {snow} | R Documentation

## Timing SNOW Clusters

### Description

Experimental functions to collect and display timing data for cluster computations.

### Usage

    snow.time(expr)
    ## S3 method for class 'snowTimingData'
    print(x, ...)
    ## S3 method for class 'snowTimingData'
    plot(x, xlab = "Elapsed Time", ylab = "Node",
                                  title = "Cluster Usage", ...)

### Arguments

`expr` | expression to evaluate
`x` | timing data object to plot or print
`xlab` | x axis label
`ylab` | y axis label
`title` | plot main title
`...` | additional arguments

### Details

`snow.time` collects and returns and returns timing information for cluster usage in evaluating `expr`. The return value is an object of class `snowTimingData`; details of the return value are subject to change. The `print` method for `snowTimingData` objects shows the total elapsed time, the total communication time between master and worker nodes, and the compute time on each worker node. The `plot`, motivated by the display produced by `xpvm`, produces a Gantt chart of the computation, with green rectangles representing active computation, blue horizontal lines representing a worker waiting to return a result, and red lines representing master/worker communications.

### Examples

      ## Not run:
    cl <- makeCluster(2,type="SOCK")
    x <- rnorm(1000000)
    tm <- snow.time(clusterCall(cl, function(x) for (i in 1:100) sum(x), x))
    print(tm)
    plot(tm)
    stopCluster(cl)

    ## End(Not run)

[Package snow version 0.4-2 Index]