Hi Lokesh, gem5 does indeed currently only capture the delay in the transition, and still “clocks” the components that are affected. A more detailed model of the PMIC and voltage regulators, battery etc can definitely be added, the transitions refined etc. The question is how much it matters, and what your ultimate goal is.
Based on the academic work I’ve seen done on DVFS I’d say there are far more serious shortcomings to be addressed (e.g. Ignoring the OS). Andreas On 16/04/2015 16:28, "Lokesh Jindal" <[email protected]> wrote: >Hello everyone > >In DVFS in real systems, there are 2 parameters that come into picture >during voltage-frequency transition. >1. "Core dead time" during which core does not execute anything and is >the time taken to actually change the frequency. >2. "voltage change time" during which the core is executing instructions. > >I have done some quick digging into the DVFS implementation in gem5. It >seems there is one parameter "transition_latency" associated with dvfs >handler. When a perlevel (V,f) change request is initiated, the handler >schedules an event that changes the perflevel (V,F) after >"transition_latency". I think this models only parameter (2) above >(voltage change time) and the parameter (1) above (core dead time) is >not modelled precisely. > >Please comment if this observation of mine seems accurate/inaccurate! > >-- >Regards >Lokesh Jindal >UW-Madison >_______________________________________________ >gem5-dev mailing list >[email protected] >http://m5sim.org/mailman/listinfo/gem5-dev -- IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No: 2557590 ARM Holdings plc, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No: 2548782 _______________________________________________ gem5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/gem5-dev
