On Wednesday 18 June 2014 04:51 PM, Nicolas Pitre wrote: > On Wed, 18 Jun 2014, Santosh Shilimkar wrote: > >> On Wednesday 18 June 2014 01:36 PM, Lorenzo Pieralisi wrote: >> [..] >>> + To correctly specify idle states timing and energy related properties, >>> + the following definitions identify the different execution phases >>> + a CPU goes through to enter and exit idle states and the implied >>> + energy metrics: >>> + >>> + ..__[EXEC]__|__[PREP]__|__[ENTRY]__|__[IDLE]__|__[EXIT]__|__[EXEC]__.. >>> + | | | | | >>> + >>> + |<------ entry ------->| >>> + | latency | >>> + |<- exit ->| >>> + | latency | >>> + |<-------- min-residency -------->| >>> + |<------- wakeup-latency ------->| >>> + >> I don't know the wakeup latency makes much sense and also correct. >> Hardware wakeup latency is actually exit latency. Is it for failed >> or abort-able ilde case ? We are adding this as a new parameter >> at least from idle states perspective. I think we should just >> avoid it. > > I explained the rationale for this parameter in a previous email but > Lorenzo didn't carry it over. To be clearer, this should be "worst case > wake-up latency". It is of interest for PMQOS. This is the maximum > delay that can be expected from the moment a wake-up event is signaled > and the moment the CPU is back operational. This is more than just exit > latency. By default this is entry_latency + exit_latency but when there > is an abortable PREP phase then it may be shorter than that. > PMQOS angle is right. It is just that the idle code is not going to do anything with this value. But I see a value adding it instead of some one doing calculation.
Thanks for clarity Nico !! regards, Santosh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
