QuPath script to benchmark tile reading performance

QuPath-Benchmark tile reading.groovy

/**
 * QuPath script to time how quickly tiles can be read from the current image.
 * 
 * Written for https://forum.image.sc/t/issue-with-qupath-and-image-with-20-channels/110900/12
 * to explore the effect of internal and external storage.
 * 
 * Written for QuPath v0.6.0
 */

// Get the current image
var server = getCurrentServer()

// Get all available tiles
var tiles = server.getTileRequestManager().getAllTileRequests()

// Request tiles in parallel (here, just using the default common thread pool)
boolean doParallel = true

// Impatient... limit the number of tiles
int maxTiles = 10000
if (tiles.size() > maxTiles)
    tiles = tiles[0..maxTiles]

// Ensure we aren't relying on the cache
getQuPath().getImageRegionStore().clearCache()

// Request each tile & count the number of pixels it contains (treating bands separately)
var stream = tiles.stream()

if (doParallel)
    stream = stream.parallel()

long startTime = System.currentTimeMillis()
long nPixels = stream.mapToLong {
    var img = server.readRegion(it.getRegionRequest())
    return img.getWidth() * img.getHeight() * img.getRaster().getNumBands() as long
}.sum()
long endTime = System.currentTimeMillis()

long timeMillis = (endTime - startTime)
double timeSeconds = timeMillis/1000.0

// Print results
println "Total time: ${GeneralTools.formatNumber(timeSeconds, 1)} seconds"
println "Tiles per second: ${GeneralTools.formatNumber(tiles.size()/timeSeconds, 1)}"
println "Pixels per ms: ${GeneralTools.formatNumber(nPixels/timeMillis, 1)}"