[jira] [Commented] (ZOOKEEPER-1657) Increased CPU usage by unnecessary SASL checks

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ZOOKEEPER-1657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13655000#comment-13655000 ] 

Hadoop QA commented on ZOOKEEPER-1657:
--------------------------------------

-1 overall.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12571944/zookeeper-hotspot-gone.png
  against trunk revision 1463329.

    +1 @author.  The patch does not contain any @author tags.

    -1 tests included.  The patch doesn't appear to include any new or modified tests.
                        Please justify why no new tests are needed for this patch.
                        Also please list what manual steps were performed to verify this patch.

    -1 patch.  The patch command could not apply the patch.

Console output: https://builds.apache.org/job/PreCommit-ZOOKEEPER-Build/1477//console

This message is automatically generated.
                
> Increased CPU usage by unnecessary SASL checks
> ----------------------------------------------
>
>                 Key: ZOOKEEPER-1657
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1657
>             Project: ZooKeeper
>          Issue Type: Bug
>          Components: java client
>    Affects Versions: 3.4.5
>            Reporter: Gunnar Wagenknecht
>            Assignee: Eugene Koontz
>              Labels: performance
>             Fix For: 3.5.0, 3.4.6
>
>         Attachments: ZOOKEEPER-1657.patch, ZOOKEEPER-1657.patch, ZOOKEEPER-1657.patch, zookeeper-hotspot-gone.png, zookeeper-hotspot.png
>
>
> I did some profiling in one of our Java environments and found an interesting footprint in ZooKeeper. The SASL support seems to trigger a lot times on the client although it's not even in use.
> Is there a switch to disable SASL completely?
> The attached screenshot shows a 10-minute profiling session on one of our production Jetty servers. The Jetty server handles ~1k web requests per minute. The average response time per web request is a few milli seconds. The profiling was performed on a machine running for >24h. 
> We noticed a significant CPU increase on our servers when deploying an update from ZooKeeper 3.3.2 to ZooKeeper 3.4.5. Thus, we started investigating. The screenshot shows that only 32% CPU time are spent in Jetty. In contrast, 65% are spend in ZooKeeper. 
> A few notes/thoughts:
> * {{ClientCnxn$SendThread.clientTunneledAuthenticationInProgress}} seems to be the culprit
> * {{javax.security.auth.login.Configuration.getConfiguration}} seems to be called very often?
> * There is quite a bit reflection involved in {{java.security.AccessController.doPrivileged}}
> * No security manager is active in the JVM: I tend to place an if-check in the code before calling {{AccessController.doPrivileged}}. When no SM is installed, the runnable can be called directly which safes cycles.

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