[jira] [Work logged] (HIVE-24537) Optimise locking in LlapTaskSchedulerService

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-24537?focusedWorklogId=601627&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-601627 ]

ASF GitHub Bot logged work on HIVE-24537:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 25/May/21 10:52
            Start Date: 25/May/21 10:52
    Worklog Time Spent: 10m 
      Work Description: maheshk114 commented on a change in pull request #2224:
URL: https://github.com/apache/hive/pull/2224#discussion_r638673230



##########
File path: llap-tez/src/java/org/apache/hadoop/hive/llap/tezplugins/LlapTaskSchedulerService.java
##########
@@ -1168,16 +1165,13 @@ public void allocateTask(Object task, Resource capability, ContainerId container
         capability, null, null, clock.getTime(), id);
     LOG.info("Received allocateRequest. task={}, priority={}, capability={}, containerId={}",
         task, priority, capability, containerId);
-    writeLock.lock();
-    try {
-      if (!dagRunning && metrics != null && id != null) {
+    if (!dagRunning) {
+      if (metrics != null && id != null) {

Review comment:
       One issue i can see is , we are setting the dagRunning to true without setting any stats. So the stats reading thread may get some junk value for numRequestedAllocations etc. is it fine ?




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Issue Time Tracking
-------------------

    Worklog Id:     (was: 601627)
    Time Spent: 0.5h  (was: 20m)

> Optimise locking in LlapTaskSchedulerService
> --------------------------------------------
>
>                 Key: HIVE-24537
>                 URL: https://issues.apache.org/jira/browse/HIVE-24537
>             Project: Hive
>          Issue Type: Sub-task
>          Components: llap
>            Reporter: Rajesh Balamohan
>            Assignee: Panagiotis Garefalakis
>            Priority: Major
>              Labels: pull-request-available
>         Attachments: Screenshot 2020-12-15 at 11.41.49 AM.png
>
>          Time Spent: 0.5h
>  Remaining Estimate: 0h
>
> 1. Read lock should suffice for "notifyStarted()".
> 2. Locking in "allocateTask()" can be optimised. 
> 3. Optimize preemptTasks() & preemptTasksFromMap(). This would help in reducing the codepath with writeLock. Currently, it iterates through all tasks.
>  
>   !Screenshot 2020-12-15 at 11.41.49 AM.png|width=847,height=446!



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