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https://issues.apache.org/jira/browse/ZOOKEEPER-1657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13770594#comment-13770594
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Flavio Junqueira commented on ZOOKEEPER-1657:
---------------------------------------------
Thanks, I'll make sure not to add the .project file and upload the committed
patch without it.
> 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: Philip K. Warren
> Labels: performance
> Fix For: 3.5.0, 3.4.6
>
> Attachments: ZOOKEEPER-1657.patch, ZOOKEEPER-1657.patch,
> ZOOKEEPER-1657.patch, 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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