[jboss-as7-dev] Optimal MSC threadpool size?

[Carlo de Wolf]

On 12/09/2011 10:34 PM, Brian Stansberry wrote:
> On 12/9/11 3:03 PM, Dimitris Andreadis wrote:
>> Brian, I am not sure I understand, especially the reconciliation bit.
>>
>> You are saying that whoever is producing the task list to feed to the pool is not breaking
>> those tasks into pieces that can be parallelized?
>>
> In 7.0 the operations that build up the in-memory configuration model,
> load extensions, call service constructors and and tell the MSC to
> install the services are all done on a single thread, called the "boot
> thread". MSC uses a thread pool to parallelize wiring together and
> starting the services, but a lot of work is done on that single thread.
>
> This single threaded boot behavior is the way AS 7.0 always worked. For
> 7.1 I added logic to execute a lot of that "boot thread" work in
> parallel. But that logic is disabled if you set
> org.jboss.server.bootstrap.maxThreads.

Still the Controller Boot Thread is busy reading away the xml while 
other threads are waiting
for something to do.

Which is why I wrote https://github.com/wolfc/jboss-as/tree/stream-ops a 
long time ago.
But this ran into stability issues with the ServiceVerificationHandler.

Brian and I already asserted that doing streaming ops now is a pain the ...
If we really want this we can take another look, but I don't see why. 
It's already #@*%ing fast.

Carlo

>
>> In any case, we seem to have many threads sitting there idle.
>>
>> I suppose, I need to look at the code in more detail.
>>
>> On 09/12/2011 22:02, Brian Stansberry wrote:
>>> If you set org.jboss.server.bootstrap.maxThreads you disable the boot
>>> time logic that tries to parallelize running all the operations that
>>> load extensions and install subsystems subsystem.
>>>
>>> Why? Because that parallelization spawns quite a number of threads, and
>>> the original intent of org.jboss.server.bootstrap.maxThreads was to
>>> control thread counts. And there's been no time to reconcile the two.
>>>
>>> On 12/9/11 11:39 AM, Dimitris Andreadis wrote:
>>>> I was experimenting a bit with the MSC threadpool size
>>>> (org.jboss.server.bootstrap.maxThreads) vs boot time and I've put the results here:
>>>>
>>>> http://community.jboss.org/wiki/ModularServiceContainer-OptimalThreadpoolSize
>>>>
>>>> On my quad-core/dual-threaded machine with 8 reported processors, the default pool size is
>>>> 16 (processors x 2). In most cases this looks like an overkill to me, i.e. you can get
>>>> pretty much the same or better results with a thread pool of 4, or even 2.
>>>>
>>>> Another conclusion seems to be that not too much stuff gets parallelized under the hood?
>>>> Even with 1 thread the default config boots pretty much in the same time, while some benefit
>>>> kicks in as soon as you have some form of I/O in the full and ha configs. But even then,
>>>> with a thread pool of 2 you achieve most of this gain.
>>>>
>>>> Do I miss something? Do you see different results?
>>>>
>>>> Just try a single threaded boot:
>>>> standalone.bat -Dorg.jboss.server.bootstrap.maxThreads=1
>>>>
>>>> I am using the latest 7.1.0.CR1-SNAPSHOT
>>>>
>>>> /D
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>>>
>