[jacorb-developer] Delay in serial communication

[Rob Ratcliff]

The profiling tool bundled with the JDK, jvisualvm, is a very nice profiling tool and may give you some insight into what's going on.  

In regards to Java's performance in real time, delays of seconds is 
Sent from my Samsung Galaxy Note™, an AT&T LTE smartphone, Android 4.0Steve Osselton <steve.osselton at prismtech.com> wrote:Might be worth taking look at what is causing the delay by using some sort
of
Java profiling tool (such as JPROF).

In general Java isn't a great choice for applications that need
deterministic behaviour,
as essentially stuff such as garbage collection makes Java pretty non
deterministic.
Would be better with a C++ ORB (OmniORB/TAO are both free/open source)
or better still a C ORB <blatent plug> such as eORB/C </blatent plug>.

Cheers Steve.

On 26 July 2012 10:53, Kujtim Hyseni <kujtimhyseni at hotmail.com> wrote:

>
> On date 29 March 2012 I posted the following message at JacORB mailing
> list:
>
> "Hello,
>
> for my project I heave developed a class (implementation class) which
> forwards requests (operations) from client to serial port, waits for
> response, receives the response and sends it back to client but it takes a
> long time to perform it. It delays in receiving the response from serial
> port. For communication with serial port I have developed a dedicated class
> which implements Runnable and SerialPortEventListener classes. My class
> communicates serially with 8051 microcontroller. Again, it seems that class
> delays in receiving the byte stream from microcontroller. Microcontroller
> has a built in serial port while my PC uses USB-to-Serial cable. When I
> communicate microcontroller with the class from usual Java program (from
> main() routine) it works fine and it takes less than a second to receive
> the response back.
>
> I did some measurements (100 requests) in two ways. In the first,
> communication class is external and is instantiated from implementation
> class. In the second, communication class is merged with implementation
> class. The results are: for first way average response time 9.33266
> seconds, minimal response time 4.984 seconds while maximal response time
> 18.015 seconds; for second way average response time 8.62625 seconds,
> minimal response time 4.969 seconds while maximal response time 16.015
> seconds. These values are unacceptable for real time applications and raise
> the question for using JacORB further.
>
>
> What do you think and suggest about?"
>
> Then I got various suggestions (from Nick Cross) such: to install JacORB
> 3.0 and provide the code samples.
>
> I now installed JacORB 3.0 and made the same tests, but, received the same
> delays - just to illustrate for 5 requests times are (in seconds): 6.735,
> 12, 8, 7 and 13. When I invoke the requests from usual java program it
> takes less than a second per request - this is normal since routines at
> this phase are void , they just return values.
>
> Again, these delays are unacceptable for out application and if not
> resolved we will abandon JacORB and move to another ORB or perhaps Web
> service technology.
>
> Can someone from JacORB developers or mailing list contributors pay some
> attention and help resolving this issue, in order to continue with my
> project and use JacORB.
>
> Kujtim Hyseni
>
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