[Richfaces-exadel] Fwd: [seam-dev] Some profiling of blockingthreads

[Alexandr Smirnov]

Jay, can you send me profiler report or a reference application ?

Jay Balunas wrote:
> I was able to update and build with RichFaces 3.3.0-SNAPSHOT and saw
> your changes.
>
> The good news is that I no longer see any blocking threads in the
> "org.ajax4jsf.application.
> AjaxViewHandler" - none at all which is great.
>
> The bad news is that the performance has not increased in any
> meaningful or repeatable way. 
>
> During my profiling I noticed a definite increase in the blocked
> threads performing JNDI lookups.  My theory is that the
> AjaxViewHandler was acting as a gate and effectively slowing down
> concurrent requests into Seam proper.  These threads now fly straight
> through and into Seam processing.  They the end up blocked with the
> other threads performing the lookups.
>
> I will continue to look at the lookup issues, and let you all know
> what I find.
>
> -Jay
>
>
> On Tue, Sep 30, 2008 at 2:05 PM, Jay Balunas <jbalunas at redhat.com
> <mailto:jbalunas at redhat.com>> wrote:
>
>     Excellent  - I will build from sources and test the changes.
>
>     I'll post the findings up on seam-dev.
>
>     -Jay
>     ----- "Nick Belaevski" <nbelaevski at exadel.com
>     <mailto:nbelaevski at exadel.com>> wrote:
>
>     > All,
>     >
>     > I've created JIRA issue for this optimization:
>     > https://jira.jboss.org/jira/browse/RF-4554 and have just fixed it.
>     >
>     > As from now ViewHandlerWrapper#fillChain method is not synchronized
>     > anymore.
>     >
>     > Best regards,
>     >   Nick Belaevski
>     >
>     > > -----Original Message-----
>     > > From: richfaces-exadel-bounces at redhat.com
>     <mailto:richfaces-exadel-bounces at redhat.com>
>     [mailto:richfaces-exadel- <mailto:richfaces-exadel->
>     > > bounces at redhat.com <mailto:bounces at redhat.com>] On Behalf Of
>     Max Rydahl Andersen
>     > > Sent: Tuesday, September 30, 2008 10:32 AM
>     > > To: Jay Balunas; richfaces-exadel at redhat.com
>     <mailto:richfaces-exadel at redhat.com>
>     > > Subject: Re: [Richfaces-exadel] Fwd: [seam-dev] Some profiling of
>     > > blockingthreads
>     > >
>     > > Sergey/Nik ? Any news on this one ?
>     > >
>     > > /max
>     > >
>     > > > Hi Guys,
>     > > >
>     > > > I have been doing some performance testing on seam applications
>     > and have
>     > > > been able to post some of the results.  One of the areas that I
>     > have
>     > > > investigated so far was blocking/waiting threads.
>     > > >
>     > > > In my example I am running 25 concurrent users and hitting the
>     > seam wiki
>     > > > example.  I am seeing blocked threads waiting on
>     > > > "org.ajax4jsf.application.AjaxViewHandler".
>     > > > I have investigated it a bit (see below), and have included some
>     > of the
>     > > > discussions on the seam-dev list.
>     > > >
>     > > > I would like to get an opinion of the synchronized fillChain
>     > method, and
>     > > > see
>     > > > if there is another way to handle this.
>     > > >
>     > > > Thoughts?
>     > > >
>     > > > Thanks,
>     > > > Jay
>     > > >
>     > > > ---------- Forwarded message ----------
>     > > > From: Emmanuel Bernard <emmanuel at hibernate.org
>     <mailto:emmanuel at hibernate.org>>
>     > > > Date: Thu, Sep 25, 2008 at 10:01 AM
>     > > > Subject: Re: [seam-dev] Some profiling of blocking threads
>     > > > To: Jay Balunas <tech4j at gmail.com <mailto:tech4j at gmail.com>>
>     > > > Cc: Pete Muir <pmuir at redhat.com <mailto:pmuir at redhat.com>>,
>     "seam-dev at lists.jboss.org <mailto:seam-dev at lists.jboss.org>" <
>     > > > seam-dev at lists.jboss.org <mailto:seam-dev at lists.jboss.org>>
>     > > >
>     > > >
>     > > >
>     > > > On  Sep 25, 2008, at 09:17, Jay Balunas wrote:
>     > > >
>     > > > org.ajax4jsf.application.AjaxViewHandler
>     > > >> --------------------------------------------
>     > > >>  - This was not a large % of the blocked threads but caught my
>     > eye as a
>     > > >> potential trouble spot because it seemed directly related to
>     > ajax
>     > > calls.
>     > > >>  - This was easier to track down and the root cause is in the
>     > > >> org.ajax4jsf.application.ViewHandlerWrapper class.
>     > > >>  - see
>     > > >>
>     > >
>     >
>     http://anonsvn.jboss.org/repos/richfaces/trunk/framework/api/src/main/java
>     > > /org/ajax4jsf/application/ViewHandlerWrapper.java
>     > > >>  - The problem is all the calls to "fillChain" which is a
>     > synchronized
>     > > >> method in the class.
>     > > >>  - We need to find out how often the "_initialized" field is
>     > false - is
>     > > >> this once a request, once for each component, etc...
>     > > >>  - it appears to be called many times - I will look further
>     into
>     > this.
>     > > >>
>     > > >>
>     > > > I will raise this the richfaces dev guys, and see what can be
>     > done.
>     > > >
>     > > >
>     > > > Using the double check lock pattern with a volatile should make
>     > things
>     > > > better. It has to be done right though :)
>     > > >
>     > > >
>     > > >
>     > >
>     > >
>     > >
>     > > --
>     > > /max
>     > >
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>
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