Re: [ovirt-devel] Thread pools and ManageExecutorService
On Mon, Jan 16, 2017 at 10:45 AM, Roy Golan <rgolan(a)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
We use 2 pools for quartz with the same implementation
- HostUpdatesCheckerService.java - internal pool
- CommandExecutor - coco's pool
There is one more pool use for vdsm event processing:
- ForkJoinPool - created with async mode set
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.
I like the idea to managed pool provided by the container but we should revised
our way of using threads first before we will take any decisions.
Following this thread, if there is no suitable bug already, I'll open one
for this.
Some code snippets:
@Resource
private ManagedExecutorService mes;
... Future f = mes.submit(() -> doThis())
The configuration in ovirt-engine.xml.in (already there today!):
<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+Conf...
[2]
http://www.adam-bien.com/roller/abien/entry/injecting_an_executorservice_...
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