[ovirt-devel] Thread pools and ManageExecutorService

[Greg Sheremeta]

On Mon, Jan 16, 2017 at 4:45 AM, Roy Golan <rgolan at redhat.com> wrote:

> Java EE 7 included ManageExecutorService in its spec. Using Wildfly (as
> certified EE 7 container) we can use it to replace our own ThreadPoolUtil
> implementation and (possibly) Quarz usage.
>
> Managed executor service is a thread pool resource, manage by the
> container and can be controlled via JMX or the startup ovirt-egine.xml.in
> facility. This means that it could be tweaked at runtime as well. The
> service has configured thread factory and queue as well, all described by
> the xml
>
> In the engine we are using mutli pools, with little to no capabilities of
> tweaking them
> - ThreadPoolUtil - our general threading facade
> - SchedulerThreadPool - the pool we create to pass to quarz
> - HostUpdatesCheckerService.java - internal pool
> - CommandExecutor - coco's pool
>
> EE gave us a standard way to handle threads, with runtime configuration
> and ability to @inject it into the code, this means once again less code
> with using something the platform already supplies with real tuninig
> abilities. I know #infra has an item quarts, this should be considered as
> well.
>
> Following this thread, if there is no suitable bug already, I'll open one
> for this.
>

+1.

We started using this for the dashboard in a recent patch [3] by Scott:

@Resource
private ManagedScheduledExecutorService scheduledExecutor;

[3]
https://gerrit.ovirt.org/#/c/67709/7/frontend/webadmin/modules/frontend/src/main/java/org/ovirt/engine/ui/frontend/server/dashboard/DashboardDataServlet.java




>
> Some code snippets:
>
> @Resource
> private ManagedExecutorService mes;
>
> ...  Future f = mes.submit(() -> doThis())
>
>
> The configuration in ovirt-engine.xml.in (already there today!):
>

Yep, added by [3] above :)



> <managed-executor-services>
>   <managed-executor-service
>   name="default"
>   jndi-name="java:jboss/ee/concurrency/executor/default"
>   context-service="default"
>   thread-factory="default"
>   hung-task-threshold="60000"
>   core-threads="5"
>   max-threads="25"
>   keepalive-time="5000"
>   queue-length="1000000"
>   reject-policy="RETRY_ABORT" />
> </managed-executor-services>
>
> Please head here for wildfly docs [1] and here [2] to see a simple example
> (from one of the members of the EG of EE, recommended blog in general)
>
> [1] https://docs.jboss.org/author/display/WFLY8/EE+Concurrency+
> Utilities+Configuration
> [2] http://www.adam-bien.com/roller/abien/entry/injecting_
> an_executorservice_with_java
>
>
>
>
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>



-- 
Greg Sheremeta, MBA
Red Hat, Inc.
Sr. Software Engineer
gshereme at redhat.com
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