IBIS Macromodel Task Group Meeting date: 13 January 2015 Members (asterisk for those attending): Altera: * David Banas ANSYS: * Dan Dvorscak * Curtis Clark Avago (LSI) Xingdong Dai Cadence Design Systems: * Ambrish Varma Brad Brim Kumar Keshavan Ken Willis Ericsson: Anders Ekholm IBM * Steve Parker Intel: Michael Mirmak Keysight Technologies: * Fangyi Rao * Radek Biernacki Maxim Integrated Products: Hassan Rafat Mentor Graphics: * John Angulo * Arpad Muranyi Micron Technology: * Randy Wolff Justin Butterfield QLogic Corp. James Zhou Andy Joy eASIC Marc Kowalski SiSoft: * Walter Katz * Todd Westerhoff * Mike LaBonte Synopsys Rita Horner Teraspeed Consulting Group: Scott McMorrow Teraspeed Labs: * Bob Ross (Note: Agilent has changed to Keysight) The meeting was led by Arpad Muranyi. ------------------------------------------------------------------------ Opens: - Arpad: We will meet Jan 20, but not Jan 27. - We should return to our normal schedule in February. - Bob: I'd like to ask about DesignCon presentations. - Will Todd have a presentation on co-optimization? - Todd: Yes - Bob: The deadline is next week. - Arpad will have an ATM committee report? - Arpad: I can put one together - Bob: Randy has one? - Randy: I will have one on C_comp -------------------------- Call for patent disclosure: - None ------------- Review of ARs: - Todd update slides for co-optimization requirements. - Done. - Arpad to review IBIS spec for min max issues. - In progress. ------------- New Discussion: Co-optimization: - Todd showed a presentation IBIS-AMI and Co-Optimization. - slide 9: - Todd: - We had requests from three people: - David: Using legacy Tx models in co-optimization. - Radek: Letting the EDA tool run co-optimization. - Arpad: Call models in correct order to capture channel response without TX EQ. - We put these into a new scenario, Scenario 3. - Radek: It is users who are asking to use Scenario 3. - Todd: For Scenario 3, meta data about the TX will have to be supplied. - slide 10: - Todd: We want to avoid running blind sweeps, but without recompiling new DLLs. - slide 11: - Todd: The requirements are similar to other scenarios because users want to do the same things. - It is important that the TX DLL do what it's told, no other tap adjustments. - Todd: Does this satisfy the requests of Radek and David? - David: It seems to satisfy mine, but the details will be important. - Radek: This looks good, but we want to operate with new models too. - It should be a user choice, whether the model or EDA tool is the master. - Walter: There are 3 scenarios and 4 configurations - The 3 scenarios are: - The models do what the hardware does. - The RX is in control. - The EDA tool is in control. - The 4 configurations are: - Legacy TX, legacy RX. - Legacy TX, new RX. - New TX, legacy RX. - New TX, new RX. - In Scenario 3 the RX may have capability but it is not used. - We want to support all scenarios and configurations. - Todd: No one is talking about Scenario 2 with models that don't understand co-optimization. - Walter: Scenario 2 could work with a legacy TX. - Scenario 1, it's unlikely a legacy model can be used for bit-by-bit emulation. - Todd: There is confusion between 2 and 3. - Walter: The EDA tool will do the best it can given model limitations. - Todd: Legacy DLLs would not accept GetWave AMI_parameters_in. - Walter: They might abort. - David: The difference between 2 and 3 is who is driving? - Todd: That is a major difference. - David: Scenario 2 says "without hardware backchannel". - Ambrish: Scenario 1 is for hardware that really has a backchannel. - Walter: The meta file to describe how to run the TX model is important. - The format will have to be carefully defined. - Whether the RX is optimizing or the EDA too, it could work. - For legacy models it will involve closing and reopening TX Init. - Todd: In Scenario 3 the simulator steps in for one or both models. - Walter: That could be done in Scenario 2 also. - Todd: That may be possible but not as easy. - David: This opens a lot of possibilities. - Scenarios 1 and 3 are clear. - Scenario 2 needs clarification. - There may be more than 3 scenarios. - Walter: Scenario 2 confuses flows with function. - It does not have to find an optimal point using control loops in the silicon. - David: So Scenario 2 means it's not limited to what the hardware on the bench can do. - It could be called "model-only optimization". - Ambrish: Should Scenario 2 be called "Init-based"? - Walter: It can be done in either Init or GetWave. - It should not be confused with statistical vs. silicon optimization. - The legacy model in Scenario 3 can only do Init optimization. - Todd changed the title of Scenario 2. - Todd: Scenario 1 is the most literal - This is what started the discussion. - Scenario 2 is to solve the same problem where the silicon doesn't automate it. - The new requests got called out in their own scenario. - The distinction between 1 and 2 is small, from a functional view. - Walter: Scenario 2 might even be used where hardware optimization exists. - This would be because it can be hard to do. - The RX can have a proxy TX to get channel information otherwise unavailable. - Todd: Scenario 2 makes us debate whether it is worthwhile to add this optimization capability. - Whether or not there really is hardware might be just a footnote, not so important. - David: These 3 scenarios seem to cover all cases. - Ambrish: Scenario 1 and 2 are driven by the RX, not so different. - Radek: And Scenario 3 is driven by the EDA tool. - And using legacy models is one application of that. - Todd: For Scenario 3 we assume one or both models are legacy. - Radek: That does not have to be the case. - Walter: It could be neither. - Todd: It is better to say one or both might not participate. - It is not automatic that the EDA tool is in control for Scenario 3. - The control function must exist somewhere. - When I say "not participating" I mean a legacy model is not doing special things for training. - It knows nothing about back-channels. - Walter: The TX participates in the simulation, but not using the new features in the BIRD. - Todd: We assumed the same message mechanism could be used for Scenario 3. - But the EDA tool would stand in for part of what one or both models need to do. - Radek: That gives us the distinction between scenarios and configurations. - The presentation mixes those things and needs to be clarified. - Walter: We should agree it should be possible to use legacy TX models, with meta-files added. - Also the exploration can be done by the RX or the EDA tool. - The BIRD should support all of that. - Scenario 3 can't be done by a tool that does time domain optimization. - Ambrish: Are you saying Scenario 3 is the primary scenario? - Walter: No, number 1 we want the case where both models fully support optimization. - Where neither do this, we are limited to Scenario 3. - But Scenario 3 can use models that do support optimization, it just won't use it. - Radek: That is in agreement what what I thought. - Walter: Arpad made the point about the CTLE need a channel response with no EQ. - This supports that by requiring a TX that can be told what to do. - Todd: 3 scenarios and 4 configurations sounds hard to explain. - We will have to present this carefully. ------------- Next meeting: 20 Jan 2015 12:00pm PT ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives