Hi Tvrtko and Joonas, > > > > > Now tiles have their own sysfs interfaces under the gt/ > > > > > directory. Because RC6 is a property that can be configured on a > > > > > tile basis, then each tile should have its own interface > > > > > > > > > > The new sysfs structure will have a similar layout for the 4 tile > > > > > case: > > > > > > > > > > /sys/.../card0 > > > > > \u251c\u2500\u2500 gt > > > > > \u2502 \u251c\u2500\u2500 gt0 > > > > > \u2502 \u2502 \u251c\u2500\u2500 id > > > > > \u2502 \u2502 \u251c\u2500\u2500 rc6_enable > > > > > \u2502 \u2502 \u251c\u2500\u2500 rc6_residency_ms > > > > > . . . > > > > > . . . > > > > > . . > > > > > \u2502 \u2514\u2500\u2500 gtN > > > > > \u2502 \u251c\u2500\u2500 id > > > > > \u2502 \u251c\u2500\u2500 rc6_enable > > > > > \u2502 \u251c\u2500\u2500 rc6_residency_ms > > > > > \u2502 . > > > > > \u2502 . > > > > > \u2502 > > > > > \u2514\u2500\u2500 power/ -+ > > > > > \u251c\u2500\u2500 rc6_enable | Original interface > > > > > \u251c\u2500\u2500 rc6_residency_ms +-> kept as existing ABI; > > > > > . | it multiplexes over > > > > > . | the GTs > > > > > -+ > > > > > > > > > > The existing interfaces have been kept in their original location > > > > > to preserve the existing ABI. They act on all the GTs: when > > > > > reading they provide the average value from all the GTs. > > > > > > > > Average feels very odd to me. I'd ask if we can get away providing an errno > > > > instead? Or tile zero data? > > > > Tile zero data is always wrong, in my opinion. If we have round-robin > > scaling workloads like some media cases, part of the system load might > > just disappear when it goes to tile 1. > > I was thinking that in conjunction with deprecated log message it wouldn't > be wrong - I mean if the route take was to eventually retire the legacy > files altogether. that's a good point... do we want to treat the legacy interfaces as an error or do we want to make them a feature? As the discussion is turning those interfaces are becoming a feature. But what are we going to do with the coming interfaces? E.g. in the future we will have the rc6_enable/disable that can be a command, so that we will add the "_store" interface per tile. What are we going to do with the above interfaces? Are we going to add a multiplexed command as well? > > When we have frequency readbacks without control, returning MAX() across > > tiles would be the logical thing. The fact that parts of the hardware can > > be clocked lower when one part is fully utilized is the "new feature". > > > > After that we're only really left with the rc6_residency_ms. And that is > > the tough one. I'm inclined that MIN() across tiles would be the right > > answer. If you are fully utilizing a single tile, you should be able to > > see it. > So we have MIN, AVG or SUM, or errno, or remove the file (which is just a > different kind of errno?) to choose from. :) in this case it would just be MIN and MAX. At the end we have here only two types of interface: frequencies and residency_ms. For the first type we would use 'max', for the second 'min'. But the question holds in case we want keep adding interfaces to the above directories. Andi
