1 files changed, 12 insertions, 10 deletions
diff --git a/streaming/src/main/scala/org/apache/spark/streaming/scheduler/rate/RateEstimator.scala b/streaming/src/main/scala/org/apache/spark/streaming/scheduler/rate/RateEstimator.scala
index d7210f64fc..7b2ef6881d 100644
--- a/streaming/src/main/scala/org/apache/spark/streaming/scheduler/rate/RateEstimator.scala
+++ b/streaming/src/main/scala/org/apache/spark/streaming/scheduler/rate/RateEstimator.scala
@@ -21,18 +21,20 @@ import org.apache.spark.SparkConf
 import org.apache.spark.streaming.Duration
 
 /**
- * A component that estimates the rate at wich an InputDStream should ingest
- * elements, based on updates at every batch completion.
+ * A component that estimates the rate at which an `InputDStream` should ingest
+ * records, based on updates at every batch completion.
+ *
+ * @see [[org.apache.spark.streaming.scheduler.RateController]]
  */
 private[streaming] trait RateEstimator extends Serializable {
 
   /**
-   * Computes the number of elements the stream attached to this `RateEstimator`
+   * Computes the number of records the stream attached to this `RateEstimator`
    * should ingest per second, given an update on the size and completion
    * times of the latest batch.
    *
-   * @param time The timetamp of the current batch interval that just finished
-   * @param elements The number of elements that were processed in this batch
+   * @param time The timestamp of the current batch interval that just finished
+   * @param elements The number of records that were processed in this batch
    * @param processingDelay The time in ms that took for the job to complete
    * @param schedulingDelay The time in ms that the job spent in the scheduling queue
    */
@@ -46,13 +48,13 @@ private[streaming] trait RateEstimator extends Serializable {
 object RateEstimator {
 
   /**
-   * Return a new RateEstimator based on the value of `spark.streaming.RateEstimator`.
+   * Return a new `RateEstimator` based on the value of
+   * `spark.streaming.backpressure.rateEstimator`.
    *
-   * The only known estimator right now is `pid`.
+   * The only known and acceptable estimator right now is `pid`.
    *
    * @return An instance of RateEstimator
-   * @throws IllegalArgumentException if there is a configured RateEstimator that doesn't match any
-   *         known estimators.
+   * @throws IllegalArgumentException if the configured RateEstimator is not `pid`.
    */
   def create(conf: SparkConf, batchInterval: Duration): RateEstimator =
     conf.get("spark.streaming.backpressure.rateEstimator", "pid") match {
@@ -64,6 +66,6 @@ object RateEstimator {
         new PIDRateEstimator(batchInterval.milliseconds, proportional, integral, derived, minRate)
 
       case estimator =>
-        throw new IllegalArgumentException(s"Unkown rate estimator: $estimator")
+        throw new IllegalArgumentException(s"Unknown rate estimator: $estimator")
     }
 }