Github user rxin commented on a diff in the pull request:
https://github.com/apache/spark/pull/11018#discussion_r51528424
--- Diff: core/src/main/scala/org/apache/spark/util/Benchmark.scala ---
@@ -99,22 +99,25 @@ private[spark] object Benchmark {
* the rate of the function.
*/
def measure(num: Long, iters: Int, outputPerIteration: Boolean)(f: Int
=> Unit): Result = {
- var totalTime = 0L
+ var bestTime = Long.MaxValue
for (i <- 0 until iters + 1) {
val start = System.nanoTime()
f(i)
val end = System.nanoTime()
- if (i != 0) totalTime += end - start
+ val runTime = end - start
+ if (runTime < bestTime) {
+ bestTime = runTime
+ }
if (outputPerIteration) {
// scalastyle:off
- println(s"Iteration $i took ${(end - start) / 1000} microseconds")
+ println(s"Iteration $i took ${runTime / 1000} microseconds")
// scalastyle:on
}
}
- Result(totalTime.toDouble / 1000000 / iters, num * iters /
(totalTime.toDouble / 1000))
+ Result(bestTime.toDouble / 1000000, num / (bestTime.toDouble / 1000))
--- End diff --
as discussed offline, I don't think this is a good idea. at the very least
if you want to compare best time, you should also report avg time, which is a
more reasonable number to compare.
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