Viewing OVM Transactions in Simvision

 Hi.

begin_tr and end_tr are empty "stub" methods in the main OVM distribution - the idea is to provide a common API for users, whilst letting each vendor provide the implementation in a way that best fits their tools.

Because of this you have to compile an extra file to get the SimVision transaction fibres working.
If you're using the OVM that ships with IUS, this file is included already in the compilation, but if you're using the ovmworld.org version, you have to compile the file separately. It's called cdns_recording.svh and is located in tools/ovm/src/cdns_additions/ inside the IUS installation directory.

The transaction fibres should show up inside the sequencer instances in the OVM class hierarchy (unless you're calling begin_tr from a different location).If you don't even see the OVM class hierarchy, there must be something wrong with your instantiation of the OVM testbench, because IUS 8.1 and 8.2 definitely show the OVM hierarchy in the Design Browser. I was going to paste a screenshot to show you what to expect, but this forum won't let me insert an image...

A final note: IUS 8.2 can send class objects to the waveforms even without transaction recording, but this is not the same as the transaction recording - the two are complimentary. You should also be able to see in the Design Browser the class objects under any instance, and the values of the class fields are shown there too. You can even descend into queues, arrays of classes etc.

Hi StephenH,

Thanks allot for your really helpful email, though unfortunately I still can't see OVM class hierarchy in IUS8.1s009

Also I couldn't find cdns_additions directory but only an empty cdns_extentions folder with no files in it?!?

The gif you sent - is it simply the Xbus OVM example? If it is, then I compiled it and run it under the specified Version and all I can see is just the xbus_tb_top module and all the class definitions bellow but no xbus_test_top class hierarchy.

Are you sure I can see it also in my version (IUS81)? because it seems from the Gif, you are using IUS82

and finally, what is the exact command line you are using. Maybe I'm missing some flags.

 Thanks and I appreciate your help,

You're right, I was using 8.2s3. I checked it in 8.1s9 and it does work, the location of the cdns_additions is:
IUS08.10.009-s/tools/ovm/src/cdns_additions/cdns_recording.svh

I used the xbus example directly, I simply copied it to my home directory and ran the compile_ius.f:

cp -r $IUS_HOME/tools/ovm/examples/xbus ~
cd ~/xbus
irun -f compile_ius.f +incdir+$IUS_HOME/tools/ovm/src -gui

Hopefully that'll work for you as well. If not, you know where to come for help ;-)

I forgot to mention - because the begin_tr is responsible for registering the transaction fibre, you will not see anything in the DesignBrowser at time 0. You have to run a short time until the 1st time the sequencer calls begin_tr, after which the transactions become visible.There isn't any work-around for this in SystemVerilog.
In the xbus example, I run for just 1 ns to see the transactions.

Thanks !!! this time it worked after I linked ovmhome to the IUS installation as you said.

Anyway, just a side effect I noticed that the results of my test case were different between the former IUS62 I used to work with

and the current IUS81. Same code but different version. Do you know what could be the reason?

All of the sudden, I get only 2 items and then transactions are stopped as if the sequencer stopped executing sequences.

(in IUS62 there were more before they stopped but also then I didn't know why they stopped long before simulation ended)

Do you know what could be the reason that transactions stopps?

Sorry I'm jumping to a totally different issue but I'm new to OVM and I'm currently trying a pilot for SV functional verification using OVM,

(Hopefully the OVM wil turn out to be usefull and convenient and not a big headache)

Thanks allot again and if you think that I'm already pushing it too much don't hesistate to say so :)

There are various posible reasons for your simulation to stop at a different time.
It sounds like you've switched OVM versions between 6.2 and 8.1 - of course 6.2 didn't come with OVM, so you were forced to download it separately, but 8.1 ships with OVM.

If you have different OVM versions, that will in turn affect the randomisation, giving you different results for the same seed.

Have a look in the sequencers and check what value of "count" was generated, this will tell you how many transactions to expect.

If you want some help looking into OVM, feel free to contact a Cadence AE. There are OVM trained experts in every region of the world now, ready to help people get started. If you're not sure who is your local AE, drop me a private message or email stephenh at cadence . com with your contact details and I'll find someone close to your location.

Enjoy!