I don't see how you came to the conclusion that only 2 service threads
are running in the container. Also, the performance will also depend on
whether or not you are reusing port stubs, as the first invocation is
extremely expensive as opposed to subsequent invocations. Here are some
throughput numbers I obtained a while back using GT4.0.4 on a dual Xeon
3GHz with HT and 32 client nodes and 20 threads at the container:
* no security: 500 WS calls per sec
* GSISecureConversation: 204 WS calls per sec
* GSITransport: 65 WS calls per sec
There are also different settings for each security mechanism, such as
encryption and integrity checks, which can affect performance. The
number above (for the 2 security cases) are with encryption.
I heard that GT4.1.x and GT4.2.x are using persistent sockets, which
hurt the performance of the GSITransport. I expect the GSITransport to
be significantly better in the latest GT version. Another thing to
remember is that these numbers reflect the re-use of port stubs on the
client side. Without re-using the port stubs, my intuition says that
the throughput would be one to two orders of magnitude lower, but I
haven't actually measured it to know for sure.
In conclusion, you think that you only have 2 threads servicing the WS
calls at the GT4 container. I believe your tests are inconclusive based
on what you described so far. Can you be more specific on the tests and
results you have done, which leads you to believe that there are only 2
threads (when in fact you have set it higher)?
Ioan
Samuel LIU wrote:
0.8sec is in -nosec scenario. Yes, in this scenario, I could not infer the 2
container thread limit. However, when I enabled signing and encryption on the
communication channel (GSI Transport) or messages (GSI Secure Conversation), I
could see the obvious delays among request processing at server side: 2
responses at a time and interleaved by about 10 seconds. Client side overhead
was ruled out by comparing starting timestamps.
My purpose of conducting this test is to measure service invocation overhead
given different security options: no security, channel level, or message level.
The performance of my service code has been tested separately.
Thanks,
Sam.
----------------------------------------
Date: Wed, 23 Jan 2008 14:39:06 -0600
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
CC: [email protected]
Subject: Re: [gt-user] WS Core containerThreads not working
If you have such short requests that they can be handled in 0.8 sec,
then how do you know that there are only 2 at a time being serviced?
Here is the test I would do to see how many threads are really running.
In the service code, add a sleep 60 sec call... and on the client, start
as many threads, which is hopefully larger than what you set as a max on
the GT4 container, something on the order of O(100s), and invoke the
service as fast as possible from all client threads. If for example you
had a max of 50 threads set on the GT4 container, you would see after 60
seconds that 50 invocations were completed successfully, then after
another 60 sec, another 50 invocations, etc... if indeed you only have 2
threads, then you would see only 2 at a time every 60 sec.
Now, about seeing performance difference in your own code (without the
sleep 60) as you increase the number of threads, it all depends on your
specific code and what the client/service are doing. Also, from my
experience, the client side is generally more heavy weight that the
service side... which means that you will need multiple concurrent
clients to generally saturate a given service.
Ioan
Samuel LIU wrote:
I am trying to test the service response time of a Grid service I wrote given
different request rate. By default, WS Core sets initial thread number to be 2.
When I started globus container w/ -nosec, I could not see much difference. All
requests were served within 0.8 sec. However, when I started container with GSI
Transport or GSI Secure Conversation settings, I could see clearly two requests
were served at a time.
The problem is: based on gt4 doc, when I changed thread settings to:
and restarted container, I saw no difference: still 2 requests were accepted at
one time, then another 2, ...
Can anyone suggest what went wrong? I am using globus 4.0.5 on a CentOS machine.
Thanks,
Sam.
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--
==================================================
Ioan Raicu
Ph.D. Candidate
==================================================
Distributed Systems Laboratory
Computer Science Department
University of Chicago
1100 E. 58th Street, Ryerson Hall
Chicago, IL 60637
==================================================
Email: [EMAIL PROTECTED]
Web: http://www.cs.uchicago.edu/~iraicu
http://dev.globus.org/wiki/Incubator/Falkon
http://www.ci.uchicago.edu/wiki/bin/view/VDS/DslCS
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