[
https://issues.apache.org/jira/browse/YARN-6163?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15862475#comment-15862475
]
ASF GitHub Bot commented on YARN-6163:
--------------------------------------
Github user kambatla commented on a diff in the pull request:
https://github.com/apache/hadoop/pull/192#discussion_r100673288
--- Diff:
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSAppAttempt.java
---
@@ -1106,6 +1111,97 @@ boolean isStarvedForFairShare() {
return !Resources.isNone(fairshareStarvation);
}
+ /**
+ * Helper method for {@link #getStarvedResourceRequests()}:
+ * Given a map of visited {@link ResourceRequest}s, it checks if
+ * {@link ResourceRequest} 'rr' has already been visited. The map is
updated
+ * to reflect visiting 'rr'.
+ */
+ private static boolean checkAndMarkRRVisited(
+ Map<Priority, List<Resource>> visitedRRs, ResourceRequest rr) {
+ Priority priority = rr.getPriority();
+ Resource capability = rr.getCapability();
+ if (visitedRRs.containsKey(priority)) {
+ List<Resource> rrList = visitedRRs.get(priority);
+ if (rrList.contains(capability)) {
+ return true;
+ } else {
+ rrList.add(capability);
+ return false;
+ }
+ } else {
+ List<Resource> newRRList = new ArrayList<>();
+ newRRList.add(capability);
+ visitedRRs.put(priority, newRRList);
+ return false;
+ }
+ }
+
+ /**
+ * Fetch a list of RRs corresponding to the extent the app is starved
+ * (fairshare and minshare). This method considers the number of
containers
+ * in a RR and also only one locality-level (the first encountered
+ * resourceName).
+ *
+ * @return list of {@link ResourceRequest}s corresponding to the amount
of
+ * starvation.
+ */
+ List<ResourceRequest> getStarvedResourceRequests() {
+ List<ResourceRequest> ret = new ArrayList<>();
+ Map<Priority, List<Resource>> visitedRRs= new HashMap<>();
+
+ Resource pending = getStarvation();
+ for (ResourceRequest rr : appSchedulingInfo.getAllResourceRequests()) {
+ if (Resources.isNone(pending)) {
+ break;
+ }
+ if (checkAndMarkRRVisited(visitedRRs, rr)) {
+ continue;
+ }
+
+ // Compute the number of containers of this capability that fit in
the
+ // pending amount
+ int ratio = (int) Math.floor(
+ Resources.ratio(scheduler.getResourceCalculator(),
+ pending, rr.getCapability()));
+ if (ratio == 0) {
+ continue;
+ }
+
+ // If the RR is only partially being satisfied, include only the
+ // partial number of containers.
+ if (ratio < rr.getNumContainers()) {
+ rr = ResourceRequest.newInstance(
+ rr.getPriority(), rr.getResourceName(), rr.getCapability(),
ratio);
+ }
+ ret.add(rr);
+ Resources.subtractFromNonNegative(pending,
+ Resources.multiply(rr.getCapability(), ratio));
+ }
+
+ return ret;
+ }
+
+ /**
+ * Notify this app that preemption has been triggered to make room for
+ * outstanding demand. The app should not be considered starved until
after
+ * the specified delay.
+ *
+ * @param delayBeforeNextStarvationCheck duration to wait
+ */
+ void preemptionTriggered(long delayBeforeNextStarvationCheck) {
+ nextStarvationCheck =
+ scheduler.getClock().getTime() + delayBeforeNextStarvationCheck;
+ }
+
+ /**
+ * Whether this app's starvation should be considered.
+ */
+ boolean shouldCheckForStarvation() {
+ long now = scheduler.getClock().getTime();
+ return now > nextStarvationCheck;
--- End diff --
> and >= shouldn't really matter. Updated to >=
> FS Preemption is a trickle for severely starved applications
> ------------------------------------------------------------
>
> Key: YARN-6163
> URL: https://issues.apache.org/jira/browse/YARN-6163
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: fairscheduler
> Affects Versions: 2.9.0
> Reporter: Karthik Kambatla
> Assignee: Karthik Kambatla
> Attachments: yarn-6163-1.patch
>
>
> With current logic, only one RR is considered per each instance of marking an
> application starved. This marking happens only on the update call that runs
> every 500ms. Due to this, an application that is severely starved takes
> forever to reach fairshare based on preemptions.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
---------------------------------------------------------------------
To unsubscribe, e-mail: yarn-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: yarn-issues-h...@hadoop.apache.org
