Re: POA threading - more details

Hi Erez,

On Thu, Sep 29, 2005 at 08:25:48PM +0300, Erez Hadad wrote:
> Hi Dion,
> 
> Your answer does seem to be the right explanation. Thank you. 
> Still, because of the large throughput difference, I would just like  to 
> verify the following, so please bear with me: Does ORBacus discriminate in 
> any way between its own threads and "outsider" threads, e.g. in the form of 
> thread-local storage, priority, etc.?
> 
> I have one more question regarding throughput using a thread pool:
> Consider the following scenario (in JOB-4.1.3/JDK-1.4.2/Linux): A server is 
> processing multiple concurrent CPU-bound requests from remote clients 
> (non-collocated) using a thread pool model. Is it likely (and why) that the 
> server throughput would drop if the client load (number of concurrent 
> requests) is considerably lower or considerably higher than the thread pool 
> size? I noticed these phenomena in my tests.
> 
> Best reagrds,
> Erez Hadad

Orbacus does differentiate its own JTC threads from non-JTC threads with
regards to TSS.  Any threads making requests to the ORB MUST be JTC
threads.  These JTC threads are implemented using the OS-specific
mechanism however and are treated the same in the system.  The JTC is a
great multi-threaded library that our customers can use for their own
needs as its cross-platform and greatly simplifies many of the
constructs needed for MT programming (as well as closly mimicking the
Java implementation).

If you have a thread-pool of size N, then it can only handle up to N
requests at once.  The other thing to remember is that a single thread
within the client can only invoke a single operation at once.  If my
client only has 3 threads making requests but my thread-pool is size 10,
then basically 7 threads are being unused in the thread-pool at all
times.  Likewise if my client has 20 threads making requests, only 10
can be serviced at a time due to the limit of the number of worker
threads in the pool.  So if you drop the number of concurrent requests
in your client, then the overall server throughput will drop since it
has left-over worker threads being unused.  If you increase the workload
in the client, then the thread-pool on the server should max out at some
throughput above which it just cannot reach.  

In order to shed some more light though I would need to see some
concrete data (calls/sec, bytes/sec, etc) to cross-reference.

Cheers.

-- 
Dion Picco, Software Engineer
IONA Technologies Inc.
Team Orbacus - Your CORBA Source
mailto:[email protected]
http://www.orbacus.com
_______________________________________________
OB-Users Mailing List - [email protected]
http://mail.ooc.nf.ca/mailman/listinfo/ob-users
Visit our support FAQ before you send a message.
http://www.orbacus.com/faq/support.html