You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@spark.apache.org by "Michael Mior (JIRA)" <ji...@apache.org> on 2017/10/20 17:32:00 UTC
[jira] [Commented] (SPARK-19007) Speedup and optimize the
GradientBoostedTrees in the "data>memory" scene
[ https://issues.apache.org/jira/browse/SPARK-19007?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16212924#comment-16212924 ]
Michael Mior commented on SPARK-19007:
--------------------------------------
[~josephkb] I'm confused why it's necessary to cache more than one RDD in the queue. It seems like there should never be a need for data from previous iterations if there's enough memory to cache the previous iteration. And if there isn't, trying to cache even more data seems like it would just make things worse.
> Speedup and optimize the GradientBoostedTrees in the "data>memory" scene
> ------------------------------------------------------------------------
>
> Key: SPARK-19007
> URL: https://issues.apache.org/jira/browse/SPARK-19007
> Project: Spark
> Issue Type: Improvement
> Components: ML
> Affects Versions: 2.0.1, 2.0.2, 2.1.0
> Environment: A CDH cluster consists of 3 redhat server ,(120G memory、40 cores、43TB disk per server).
> Reporter: zhangdenghui
> Priority: Minor
> Original Estimate: 168h
> Remaining Estimate: 168h
>
> Test data：80G CTR training data from criteolabs(http://criteolabs.wpengine.com/downloads/download-terabyte-click-logs/ ) ,I used 1 of the 24 days' data.Some features needed to be repalced by new generated continuous features，the way to generate the new features refers to the way mentioned in the xgboost's paper.
> Recource allocated: spark on yarn, 20 executors, 8G memory and 2 cores per executor.
> Parameters: numIterations 10, maxdepth 8, the rest parameters are default
> I tested the GradientBoostedTrees algorithm in mllib using 80G CTR data mentioned above.
> It totally costs 1.5 hour, and i found many task failures after 6 or 7 GBT rounds later.Without these task failures and task retry it can be much faster ,which can save about half the time. I think it's caused by the RDD named predError in the while loop of the boost method at GradientBoostedTrees.scala,because the lineage of the RDD named predError is growing after every GBT round, and then it caused failures like this :
> (ExecutorLostFailure (executor 6 exited caused by one of the running tasks) Reason: Container killed by YARN for exceeding memory limits. 10.2 GB of 10 GB physical memory used. Consider boosting spark.yarn.executor.memoryOverhead.).
> I tried to boosting spark.yarn.executor.memoryOverhead but the meomry it needed is too much (even increase half the memory can't solve the problem) so i think it's not a proper method.
> Although it can set the predCheckpoint Interval smaller to cut the line of the lineage but it increases IO cost a lot.
> I tried another way to solve this problem.I persisted the RDD named predError every round and use pre_predError to record the previous RDD and unpersist it because it's useless anymore.
> Finally it costs about 45 min after i tried my method and no task failure occured and no more memeory added.
> So when the data is much larger than memory, my little improvement can speedup the GradientBoostedTrees 1~2 times.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org