Re: [jetty-users] Contention in ServletHolder.handle()

[Jan Bartel <janb@xxxxxxxxxxx>]

Daniel,

The only reason you would set the initOrder is to avoid the extra call
to getServlet() in the handle() method. It won't make any difference
to whether your servlet is properly initialized or not, as the code
specifically handles an externally provided servlet instance on
startup.

Jan

On 12/05/2014, Daniel Feist <dfeist@xxxxxxxxx> wrote:
> After doing some performance testing, while contention shows in
> profiler clearly the performance impact is not significant I don't
> thnk, so this would just be minor cleanup/optimization.
>
> Was i right when i set I need to use "initOrder" to ensure it gets
> initialized at startup?
>
> I should really just be implementing a handler, but current
> implementation uses a servlet.
>
> thanks!
>
> On Mon, May 12, 2014 at 5:15 PM, Jan Bartel <janb@xxxxxxxxxxx> wrote:
>> Daniel,
>>
>> let me see if I can prevent the call to getServlet() in the case where
>> you provide a pre-constructed servlet. I'll do some testing and get
>> back to you - I need to confirm that the handling of that would be ok
>> for cases where the servlet may have been made unavailable etc etc as
>> well.
>>
>> Jan
>>
>> On 12/05/2014, Daniel Feist <dfeist@xxxxxxxxx> wrote:
>>> Hi,
>>>
>>> Yes.  I agree this is needed is 'initOnStartup' is not configured, was
>>> trying to work out why the synchonrized block was needed at all for
>>> the 'initOnStartup' case though.
>>>
>>> That said, the reason reason I was seeing contention is probably
>>> primarily due to org.eclipse.jetty.servlet.ServletHolder.getServlet()
>>> because my servlet doesn't have 'initOnStartup' set.
>>>
>>> In my use case I embed jetty and provide Jetty with a
>>> pre-instantiated/configured servlet instance wrapped in a
>>> ServletHolder.  I guess i need to set the somewhat unobvious initOrder
>>> to non-0 to configure this and reduce the contention?
>>>
>>> thanks!
>>>
>>>
>>>
>>> On Mon, May 12, 2014 at 11:15 AM, Jan Bartel <janb@xxxxxxxxxxx> wrote:
>>>> Daniel,
>>>>
>>>> Not sure exactly the lines in ServletHolder you're referring to, but I
>>>> assume its the synchronized block around line 652? If so, then this
>>>> code guards the initial startup of a servlet - if it isn't
>>>> load-on-startup, then any request coming in can initialize it.
>>>> Therefore, if you have multiple concurrent requests, you need to
>>>> protect the servlet startup so it happens only once.
>>>>
>>>> Jan
>>>>
>>>> On 8 May 2014 22:43, Daniel Feist <dfeist@xxxxxxxxx> wrote:
>>>>> Hi,
>>>>>
>>>>> I've been doing some testing/benchmarking of Jetty 8 with Mule ESB and
>>>>> seeming a decent amount of contention where it doesn't seem that
>>>>> synchronization is required.
>>>>>
>>>>> My test scenario is just a simple echo, all i do is read the request
>>>>> stream and then respond.  The contention i'm seeing can be seen here:
>>>>>
>>>>> https://www.dropbox.com/s/bbkdsk7ndfpzoj9/Screen%20Shot%202014-05-08%20at%209.35.34%20PM.png
>>>>>
>>>>> Inspecting the code, I can't understand why this needs to even be
>>>>> synchonrized.
>>>>>
>>>>> Any thoughts? Is there a config option I should be using that i'm not?
>>>>>  Is my test scenario unrealistic?
>>>>>
>>>>> thanks!
>>>>> Dan
>>>>> _______________________________________________
>>>>> jetty-users mailing list
>>>>> jetty-users@xxxxxxxxxxx
>>>>> https://dev.eclipse.org/mailman/listinfo/jetty-users
>>>>
>>>>
>>>>
>>>> --
>>>> Jan Bartel <janb@xxxxxxxxxxx>
>>>> www.webtide.com
>>>> 'Expert Jetty/CometD developer,production,operations advice'
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>>
>>
>> --
>> Jan Bartel <janb@xxxxxxxxxxx>
>> www.webtide.com
>> 'Expert Jetty/CometD developer,production,operations advice'
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>> https://dev.eclipse.org/mailman/listinfo/jetty-users
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-- 
Jan Bartel <janb@xxxxxxxxxxx>
www.webtide.com
'Expert Jetty/CometD developer,production,operations advice'