Re: SDL-News: How to accelerate the SDL simulations


Subject: Re: SDL-News: How to accelerate the SDL simulations
From: Mike Rudnick (rudnick#appairent.com)
Date: Thu Mar 18 2004 - 15:41:06 GMT


As Anthony points out, you didn't mention what SDL implementation/tool you are using. What are you using? And if it's Tau, are you running on a windows box or under unix?

I'll assume for the moment you are using Telelogic Tau, though these common-sense principles will probably apply to other implementations as well. As previously pointed out, the primary factor limiting how fast your simulation runs is CPU cycles on the machine running the simulation. So anything you can to reduce the number of cycles needed, or increase the number of cycles available will help. Andreas made a suggestion on the reducing-number-of-cycles-needed side of the equation. Tony provided some insight as to how Tau's simulation runs in its event-driven simulation mode.

I'd suggest you try running the simulation from the command prompt rather than via the Organizer and it's suite of interactive user interface (UI) windows/applications. The cycles spent to run the window UI display stuff are wasted cycles from the simulation perspective. Likewise for tracing and logs - try running with all tracing/logging turned off versus turned on to see how much that's costing you cycle-wise. Then you can put back only essential tracing/logging.

Apart from limiting cycles wasted on OS/UI stuff, you can try to optimize both your executable, ie, see if you can turn up the optimization level on the compiler used to build the SDL simulation executable. Check to see if there's other run-time cycle-usage optimizations available in the SDL run-time system code. For example, perhaps unused cycle-wasting features in the SDL simulation run-time system can be turned off or compiled out.

Finally, you can try expanding upon what Andreas and Tony said by optimizing the SDL model being simulated, potentially a great source of cycle savings.

Please let me know if any of this helps,
  Mike

Mike Rudnick
Senior Protocol Engineer
QoS Engineer
Appairent Technologies
150 Lucius Gordon Dr., Suite 211
West Henrietta, NY 14586
rudnick#appairent.com
phone: 585.214.2454
fax: 585.214.2461
  ----- Original Message -----
  From: Yang Yang
  To: sdlnews#sdl-forum.org
  Sent: Thursday, March 18, 2004 6:42 AM
  Subject: SDL-news: How to accelerate the SDL simulations

  Become an SDL Forum Society member <http://www.sdl-forum.org/Society/members.htm>
  The originator of this message is responsible for its content.
  -----From "Yang Yang" <yy01#mails.tsinghua.edu.cn> to sdlnews -----

  Hi,members,
    I am now simulating the designed routing protocol in a network which consists of
  25 nodes. And we all know in SDL, the time is not the real time, but a virtual
  scheduled concept. I find out that the simulation is very slow. It will take me 2
  days to finish the simulation of just 5000 time units. CPU in my computer is P4
  2.4C, and the memory is 512M DDR.
    I want to ask how I can accelerate the simulations? Is setting the trace value
  to 0(forbidding the display of the trace) useful? Any other suggestions?
  Thanks in advance!

  Yang

  --End text from "Yang Yang" <yy01#mails.tsinghua.edu.cn> to sdlnews ---
  For extra SDL Forum Society benefits join at <http://www.sdl-forum.org/Society/members.htm>
  For help, email "majordomo#sdl-forum.org" with the body of your email as:
      help
  or (iff this does not answer your question) email: owner-sdlnews#sdl-forum.org

As Anthony points out, you didn't mention what SDL implementation/tool you are using.  What are you using?  And if it's Tau, are you running on a windows box or under unix?
 
I'll assume for the moment you are using Telelogic Tau, though these common-sense principles will probably apply to other implementations as well.  As previously pointed out, the primary factor limiting how fast your simulation runs is CPU cycles on the machine running the simulation.  So anything you can to reduce the number of cycles needed, or increase the number of cycles available will help.  Andreas made a suggestion on the reducing-number-of-cycles-needed side of the equation.  Tony provided some insight as to how Tau's simulation runs in its event-driven simulation mode.
 
I'd suggest you try running the simulation from the command prompt rather than via the Organizer and it's suite of interactive user interface (UI) windows/applications.  The cycles spent to run the window UI display stuff are wasted cycles from the simulation perspective.  Likewise for tracing and logs - try running with all tracing/logging turned off versus turned on to see how much that's costing you cycle-wise.  Then you can put back only essential tracing/logging. 
 
Apart from limiting cycles wasted on OS/UI stuff, you can try to optimize both your executable, ie, see if you can turn up the optimization level on the compiler used to build the SDL simulation executable.  Check to see if there's other run-time cycle-usage optimizations available in the SDL run-time system code.  For example, perhaps unused cycle-wasting features in the SDL simulation run-time system can be turned off or compiled out. 
 
Finally, you can try expanding upon what Andreas and Tony said by optimizing the SDL model being simulated, potentially a great source of cycle savings.
 
Please let me know if any of this helps,
  Mike
 
Mike Rudnick
Senior Protocol Engineer
QoS Engineer
Appairent Technologies
150 Lucius Gordon Dr., Suite 211
West Henrietta, NY  14586
rudnick#appairent.com
phone: 585.214.2454
fax: 585.214.2461
----- Original Message -----
From: Yang Yang
To: sdlnews#sdl-forum.org
Sent: Thursday, March 18, 2004 6:42 AM
Subject: SDL-News: How to accelerate the SDL simulations

Become an SDL Forum Society member <http://www.sdl-forum.org/Society/members.htm>
The originator of this message is responsible for its content.
-----From "Yang Yang" <yy01#mails.tsinghua.edu.cn> to sdlnews  -----

Hi,members,
  I am now simulating the designed routing protocol in a network which consists of
25 nodes. And we all know in SDL, the time is not the real time, but a virtual
scheduled concept. I find out that the simulation is very slow. It will take me 2
days to finish the simulation of just 5000 time units. CPU in my computer is P4
2.4C, and the memory is 512M DDR.
  I want to ask how I can accelerate the simulations? Is setting the trace value
to 0(forbidding the display of the trace) useful? Any other suggestions?
Thanks in advance!

Yang


--End text from "Yang Yang" <yy01#mails.tsinghua.edu.cn> to sdlnews ---
For extra SDL Forum Society benefits join at <http://www.sdl-forum.org/Society/members.htm>
For help, email "majordomo#sdl-forum.org" with the body of your email as:
    help
or (iff this does not answer your question) email: owner-sdlnews#sdl-forum.org
--End text from "Mike Rudnick" to sdlnews --- For extra SDL Forum Society benefits join at



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