[jira] [Commented] (THRIFT-3891) TNonblockingServer configured with more than one IO threads does not always return from serve() upon stop()

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

    [ https://issues.apache.org/jira/browse/THRIFT-3891?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15462646#comment-15462646 ] 

ASF GitHub Bot commented on THRIFT-3891:
----------------------------------------

GitHub user nsuke opened a pull request:

    https://github.com/apache/thrift/pull/1080

    THRIFT-3891 TNonblockingServer configured with more than one IO threa…

    …ds does not always return from serve() upon stop()
    
    imported from JIRA issue.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/nsuke/thrift THRIFT-3891

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/thrift/pull/1080.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1080
    
----
commit f32a79088f0b2309d53af519677e6f103b3b8c6a
Author: Buğra Gedik <bg...@gmail.com>
Date:   2016-09-04T08:18:15Z

    THRIFT-3891 TNonblockingServer configured with more than one IO threads does not always return from serve() upon stop()

----


> TNonblockingServer configured with more than one IO threads does not always return from serve() upon stop()
> -----------------------------------------------------------------------------------------------------------
>
>                 Key: THRIFT-3891
>                 URL: https://issues.apache.org/jira/browse/THRIFT-3891
>             Project: Thrift
>          Issue Type: Bug
>          Components: C++ - Library
>    Affects Versions: 0.9.3
>            Reporter: Buğra Gedik
>            Priority: Minor
>         Attachments: patch.diff
>
>
> Using {{TNonblockingServer}}, when the number of IO threads is > 1, there is race condition in which {{stop()}} does not properly unblock {{serve()}}. 
> The problem manifests itself when {{stop()}} is called (obviously from a different thread) soon after {{serve()}}. 
> The core issue is that, {{event_base_loopbreak()}} is called within the {{stop()}} sequence without checking whether the IO thread has actually entered its event loop. The documentation of {{event_base_loopbreak()}} says (http://www.wangafu.net/~nickm/libevent-book/Ref3_eventloop.html)
> {quote}
> Note also that event_base_loopexit(base,NULL) and event_base_loopbreak(base) act differently when no event loop is running: loopexit schedules the next instance of the event loop to stop right after the next round of callbacks are run (as if it had been invoked with EVLOOP_ONCE) whereas loopbreak only stops a currently running loop, and has no effect if the event loop isn’t running.
> {quote}
> Attached is a patch (against the released 0.9.3 version of the codebase).



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