ISim terminated in unexpected manner

Hi,

I have a generic design for processing FFT, where I decide the number of points in the beginning. The design is working ok, for anything less than 4096 points, but when I put the number of points to 4096 I will get a message of:


This message is not new to me, but for all the previous cases there was a descriptive message of which module/signal has caused it. Do you guys have this experience?

Thanks!

Not that it has any bearing on the problem, but why would you run a simulation with 1 fs resolution? That is not a reasonable value. 1 ps resolution is normally required by PLL models from Xilinx and Altera, but 1 fs?

You've neglected to tell us the following:
1. OS
2. ISE version
3. Memory in machine running simulation
4. did you look at isim.log
5. Running isim from a command line or through the GUI.

Have you watched the task manager when it's loading the simulation. Are you sure it's not crashing due to running out of memory?

Hey, I tried to watch task manager, I see a strange thing. Right on the start the Memory the ISim takes increases to around 500MB and then wefault.exe(Windows problem reporting) started and just then ISim displayed the above message. I am running in a 3.5GB usable mem machine, even while it is running physical memory usage was around 60%. So, I can't be sure of memory shortage.

Win 7(32 bit), 14.7 ISE and running ISim from GUI.
Here is the report from isim.log:

Btw, I also tried to change the time resolution to 1ps, didn't succeed.

SharpWeapon said:

Hey, I tried to watch task manager, I see a strange thing. Right on the start the Memory the ISim takes increases to around 500MB and then wefault.exe(Windows problem reporting) started and just then ISim displayed the above message.

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That pretty much says the testbench_isim_beh.exe executable produced by the tools crashed.

I am running in a 3.5GB usable mem machine, even while it is running physical memory usage was around 60%. So, I can't be sure of memory shortage.

Click to expand...

Your machine regularly runs with 60% memory utilization after boot up? :-o

Try running the testbench_isim_beh.exe -tclbatch isim.cmd from a command line window. Basically load the simulation executable without the waveforms and the GUI to see if you can even load the design. How big is testbench_isim_beh.exe?

If none of my suggestions work. Perhaps you should post the testbench and code so someone else can try compiling the simulation.

Btw, I also tried to change the time resolution to 1ps, didn't succeed.

Click to expand...

Didn't expect it to. You just don't need that kind of resolution unless your running multi-GHz simulations (1 ns period is a GHz, 1000 time units of simulator resolution at 1 ps).

- - - Updated - - -

Just thought of something you might try. Run the simulation with a smaller FFT size and check how much memory it uses after it's all loaded. If you're using a lot more swap space after it loads then your 4K FFT sim is probably just running out of memory.

Your machine regularly runs with 60% memory utilization after boot up? :-o

Click to expand...

I mean there is still enough space(40%) not to run out of memory.

Tried running from command line, the same message appeared and testbench_isim_beh.exe is 81KB.

Just thought of something you might try. Run the simulation with a smaller FFT size and check how much memory it uses after it's all loaded. If you're using a lot more swap space after it loads then your 4K FFT sim is probably just running out of memory.

Click to expand...

A bit less memory usage(55-56%) than before, for smaller sizes.

SharpWeapon said:

A bit less memory usage(55-56%) than before, for smaller sizes.

Click to expand...

but in that case it loads?

Are you sure there isn't some problem with how you handled the change in FFT size?

I'm assuming you've tried to recompile the design after deleting the simulation subdirectories. I've sometimes have had issues with Vivado xsim if killed the compilation of the exe before it completed. Not sure if ISE isim would exhibit similar issues.

You might have to post the design so someone can try running it to see if it's something inherent in the design or a problem with your setup.

..I've sometimes have had issues with Vivado xsim if killed the compilation of the exe before it completed. Not sure if ISE isim would exhibit similar issues.

Click to expand...

Finally you nailed it!!!:thumbsup: After you remind me, I cleaned up the project files and rerun again, works superb! Thanks a lot man! :wink:

Sorry I didn't think of having you try that first. I sort of do that by habit...helps when you run from command line (my script does it automatically).