linux-kernel - Re: [PATCH 6/7] thermal: netlink: Add a new event to notify CPU capabilities change

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Date:   Thu, 9 Dec 2021 08:03:46 -0800
From:   Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-pm@...r.kernel.org, x86@...nel.org,
        linux-doc@...r.kernel.org, Len Brown <len.brown@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Aubrey Li <aubrey.li@...ux.intel.com>,
        Amit Kucheria <amitk@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Ricardo Neri <ricardo.neri@...el.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/7] thermal: netlink: Add a new event to notify CPU
 capabilities change

On Tue, Nov 30, 2021 at 10:29:46AM +0100, Daniel Lezcano wrote:
> On 06/11/2021 02:33, Ricardo Neri wrote:
> > From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> > 
> > Add a new netlink event to notify change in CPU capabilities in terms of
> > performance and efficiency.
> > 
> > Firmware may change CPU capabilities as a result of thermal events in the
> > system or to account for changes in the TDP (thermal design power) level.
> > 
> > This notification type will allow user space to avoid running workloads
> > on certain CPUs or proactively adjust power limits to avoid future events.
> > 
> 
> [ ... ]
> 
> > +	[THERMAL_GENL_ATTR_CPU_CAPABILITY_ID]	= { .type = NLA_U32 },
> > +	[THERMAL_GENL_ATTR_CPU_CAPABILITY_PERF]	= { .type = NLA_U32 },
> > +	[THERMAL_GENL_ATTR_CPU_CAPABILITY_EFF]	= { .type = NLA_U32 },
> >  };
> 
> AFAIU, 0 <= perf < 256 and 0 <= eff < 256, right?
> 
> Is the following true?
> 
> 	0 <= perf + eff < 256

No, they are not. They are set independently.

Thanks and BR,
Ricardo