hadoop-yarn-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Miklos Szegedi (JIRA)" <j...@apache.org>
Subject [jira] [Created] (YARN-5686) DefaultContainerExecutor random working dir algorigthm skews results
Date Wed, 28 Sep 2016 23:46:20 GMT
Miklos Szegedi created YARN-5686:
------------------------------------

             Summary: DefaultContainerExecutor random working dir algorigthm skews results
                 Key: YARN-5686
                 URL: https://issues.apache.org/jira/browse/YARN-5686
             Project: Hadoop YARN
          Issue Type: Bug
            Reporter: Miklos Szegedi
            Priority: Minor


{code}
long randomPosition = RandomUtils.nextLong() % totalAvailable;
    ...
    while (randomPosition > availableOnDisk[dir]) {
      randomPosition -= availableOnDisk[dir++];
    }
{code}

The code above selects a disk based on the random number weighted by the free space on each
disk respectively. For example, if I have two disks with 100 bytes each, totalAvailable is
200. The value of randomPosition will be 0..199. 0..99 should select the first disk, 100..199
should select the second disk inclusively. Random number 100 should select the second disk
to be fair but this is not the case right now.

We need to use 
{code}
while (randomPosition >= availableOnDisk[dir])
{code}
instead of
{code}
while (randomPosition > availableOnDisk[dir])
{code}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: yarn-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: yarn-issues-help@hadoop.apache.org


Mime
View raw message