Github user pwendell commented on a diff in the pull request:
https://github.com/apache/spark/pull/4067#discussion_r23913204
--- Diff: core/src/main/scala/org/apache/spark/CacheManager.scala ---
@@ -47,9 +49,13 @@ private[spark] class CacheManager(blockManager:
BlockManager) extends Logging {
val inputMetrics = blockResult.inputMetrics
val existingMetrics = context.taskMetrics
.getInputMetricsForReadMethod(inputMetrics.readMethod)
- existingMetrics.addBytesRead(inputMetrics.bytesRead)
+ existingMetrics.incBytesRead(inputMetrics.bytesRead)
- new InterruptibleIterator(context,
blockResult.data.asInstanceOf[Iterator[T]])
+ val iter = blockResult.data.asInstanceOf[Iterator[T]]
+ new InterruptibleIterator(context,
AfterNextInterceptingIterator(iter, (next: T) => {
+ existingMetrics.incRecordsRead(1)
--- End diff --
Hm, this seems prohibitively expensive. This will add multiple function
invocations and force hardware locking for every +next+ call (or at least some
internal checks if it's changed to +volatile+). Have you looked at the
performance implications of this? For instance, try reading from a good amount
of off-heap data from many threads and seeing if it regresses performance.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
