On Tue, 2021-11-09 at 17:51 +0000, Lukasz Luba wrote: > > > On 11/9/21 2:15 PM, Srinivas Pandruvada wrote: > > On Tue, 2021-11-09 at 13:53 +0000, Lukasz Luba wrote: > > > Hi Srinivas, > > > > > > On 11/9/21 1:23 PM, Srinivas Pandruvada wrote: > > > > Hi Lukasz, > > > > > > > > On Tue, 2021-11-09 at 12:39 +0000, Lukasz Luba wrote: > > > > > Hi Ricardo, > > > > > > > > > > > > > > > On 11/6/21 1:33 AM, Ricardo Neri wrote: > > > > > > From: Srinivas Pandruvada < > > > > > > srinivas.pandruvada@xxxxxxxxxxxxxxx> > > > > > > > > > > > > Add a new netlink event to notify change in CPU capabilities > > > > > > in > > > > > > terms of > > > > > > performance and efficiency. > > > > > > > > > > Is this going to be handled by some 'generic' tools? If yes, > > > > > maybe > > > > > the values for 'performance' might be aligned with capacity > > > > > [0,1024] ? Or are they completely not related so the mapping is > > > > > simply impossible? > > > > > > > > > > > > > That would have been very useful. > > > > > > > > The problem is that we may not know the maximum performance as > > > > system > > > > may be booting with few CPUs (using maxcpus kernel command line) > > > > and > > > > then user hot adding them. So we may need to rescale when we get > > > > a > > > > new > > > > maximum performance CPU and send to user space. > > > > > > > > We can't just use max from HFI table at in instance as it is not > > > > necessary that HFI table contains data for all CPUs. > > > > > > > > If HFI max performance value of 255 is a scaled value to max > > > > performance CPU value in the system, then this conversion would > > > > have > > > > been easy. But that is not. > > > > > > I see. I was asking because I'm working on similar interface and > > > just wanted to understand your approach better. In my case we > > > would probably simply use 'capacity' scale, or more > > > precisely available capacity after subtracting 'thermal pressure' > > > value. > > > That might confuse a generic tool which listens to these socket > > > messages, though. So probably I would have to add a new > > > THERMAL_GENL_ATTR_CPU_CAPABILITY_* id > > > to handle this different normalized across CPUs scale. > > I can add a field capacity_scale. In HFI case it will always be 255. > > In > > your cases it will 1024. > > > > > > Sounds good, with that upper limit those tools would not build > up assumptions (they would have to parse that scale value). > Although, I would prefer to call it 'performance_scale' if you don't > mind. Sure. Thanks, Srinivas > I've done similar renaming s/capacity/performance/ in the Energy Model > (EM) some time ago [1]. Some reasons: > - in the scheduler we have 'Performance Domains (PDs)' > - for GPUs we talk about 'performance', because 'capacity' sounds odd > in that case > > [1] > https://lore.kernel.org/linux-pm/20200527095854.21714-2-lukasz.luba@xxxxxxx/
