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From Remy Maucherat <r...@apache.org>
Subject Re: Interactions with org.apache.coyote.Request/Response
Date Tue, 18 Oct 2005 09:39:52 GMT
Irving, Dave wrote:
> 
>> There's no reason to use crap stuff like a BAOS. Just append byte
>> arrays to a buffer.
> 
> I'll take a look at how this is done in tomcat at the moment.

The lower level code doesn't deal with IS/OS constructs, only with byte 
arrays.

>>> - It looks like I'll have to implement the ActionHook stuff to
>>> deal with call-backs from the request / response. Is there
>>> anything else I'll need to do?
> 
>> No.
> 
> That's handy. The thing that's currently puzzling me a little is that
> the Response seems to have an associated stream, but doesn't really
> write to it itself. When should I actually go about pushing stuff in
> to that buffer at the connector level? In response to action
> call-backs?

There's Response.doWrite, and that's it.

>>> - Im planning to have my "NIOHttpProcessor" use a CoyoteAdapter
>>> the same way the Http11Processor does. Does this sound reasonable
>>> enough?
> 
>> I don't care how how you name your classes ;)
> 
> I was asking more about whether the existing CoyoteAdapter is likely
> to be re-usable in such a scenario

If it's not reusable, then you are in trouble ;)

>>> Any pointers / help / advice would be gratefully received.
> 
>> Obviously, you can feel free to experiment all you want, but such a
>> specific connector will not be included in Tomcat. Scalability will
>> be far more limited with your design than even with the fully
>> threaded Tomcat. If all the server is doing are small requests and
>> responses, then it will work well (however, the hybrid model also
>> likes this scenario, so I don't think it will even improve on
>> that), otherwise it will just break.
> 
> Sure, there's no way I could see this being included in Tomcat
> "proper". Like I said, its just a prototype to see if it solves a
> specific problem im experiencing (I just cant configure tomcat with
> 20,000 threads). However, your reply confuses me somewhat. These are
> not going to be small requests / responses: In fact, they are likely
> to be fairly large multi-part messages (SOAP and the like). In
> addition, the processing latency is going to be large (potentially up
> to 15 seconds per request). Surely this is a reason ** for **
> breaking the thread per connection model? Why would it break with
> anything other than small requests and responses? (There's nothing to
> stop parsing to be offloaded to a small - probably CPU count matched
> - thread pool)?

If you get large responses, then I figure GC (and maybe memory usage) is 
going to be a problem (all your buffers will pile up, and most likely 
they are not going to be short lived objects). A thread will still be 
needed to run the servlet, so I hope the amount of time spent in the 
service method will be lower than 15 seconds. Otherwise, there's no real 
solution besides having a large amount of threads.

Personally, I did experiment and implement a hybrid model for connection 
handling, which improves on some aspects of the regular thread per 
connection model, while keeping its benefits.

Rémy

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