Comments on: Should you use VMM Callbacks or TLM Analysis ports? http://www.vmmcentral.org/vmartialarts/2010/01/should-you-use-vmm-callbacks-or-tlm-analysis-ports/ A Blog on Verification Methodology Fri, 30 Sep 2011 08:39:43 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Dhaval http://www.vmmcentral.org/vmartialarts/2010/01/should-you-use-vmm-callbacks-or-tlm-analysis-ports/comment-page-1/#comment-811 Dhaval Mon, 01 Feb 2010 05:05:37 +0000 http://www.vmmcentral.org/vmartialarts/?p=860#comment-811 Calbbacks are basically introduced to keep xactor reusable. Passing transaction to sb/cov is one of the side-use of the callback. TLM is intended to be used as a comunication mechanism. Dhaval Calbbacks are basically introduced to keep xactor reusable. Passing transaction to sb/cov is one of the side-use of the callback. TLM is intended to be used as a comunication mechanism.

Dhaval

]]> By: Shunty http://www.vmmcentral.org/vmartialarts/2010/01/should-you-use-vmm-callbacks-or-tlm-analysis-ports/comment-page-1/#comment-810 Shunty Thu, 28 Jan 2010 04:46:22 +0000 http://www.vmmcentral.org/vmartialarts/?p=860#comment-810 Thanks Prashanth this post is indeed informative and relieves users when it comes to VMM-1.2 development/migration related issues/debates, to choose between callbacks and analysis ports. Your last line in this "Both analysis port and callback can also be provided, publishing analysis port after callbacks." I think what you mean to say here is, "Instantiaing the analysis ports in the callback classes." As far as my experience with vmm-1.2 says, This is something users would choose in the most cases. Reasons: Callbacks are the lovely and amazing creatures introduced by Synopsys brains, to add the flexible hook up points in the xactors. At the same time, when Era has changed to interoperability between mulitple languages, no one wants to stay back and avoid using TLMs because its great to keep window for everything in the xactors, who knows where it could be REUSED tomorrow. To use the both the things at the same time, I would suggest to Keep the hook up points in your Xactors as callbacks only, and instantiate the required TLM ports in the Callbacks. This will, -> Keep your xactor flexible to Change the transaction before you pass it to the observers using analysis ports. -> It will keep a window for every advantage of Callbacks like as you said, inserting delays, error injections etc. -> Add the TLM interoperability advantage in your xactor as you have TLM ports in the callbacks, So what I indicate here is, "Every VMM-1.1 xactor which has callbacks at proper points is of-course interoperable using TLM with foreign code/VMM-1.2 code which uses TLM" Cheers, Shunty Thanks Prashanth this post is indeed informative and relieves users when it comes to VMM-1.2 development/migration related issues/debates, to choose between callbacks and analysis ports.

Your last line in this
“Both analysis port and callback can also be provided, publishing analysis port after callbacks.”
I think what you mean to say here is, “Instantiaing the analysis ports in the callback classes.”

As far as my experience with vmm-1.2 says, This is something users would choose in the most cases.

Reasons:
Callbacks are the lovely and amazing creatures introduced by Synopsys brains, to add the flexible hook up points in the xactors. At the same time, when Era has changed to interoperability between mulitple languages, no one wants to stay back and avoid using TLMs because its great to keep window for everything in the xactors, who knows where it could be REUSED tomorrow.

To use the both the things at the same time, I would suggest to Keep the hook up points in your Xactors as callbacks only, and instantiate the required TLM ports in the Callbacks. This will,
-> Keep your xactor flexible to Change the transaction before you pass it to the observers using analysis ports.
-> It will keep a window for every advantage of Callbacks like as you said, inserting delays, error injections etc.
-> Add the TLM interoperability advantage in your xactor as you have TLM ports in the callbacks, So what I indicate here is, “Every VMM-1.1 xactor which has callbacks at proper points is of-course interoperable using TLM with foreign code/VMM-1.2 code which uses TLM”

Cheers,
Shunty

]]>