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

On 09/12/2021 17:03, Ricardo Neri wrote:

On Tue, Nov 30, 2021 at 10:29:46AM +0100, Daniel Lezcano wrote:

quoted

On 06/11/2021 02:33, Ricardo Neri wrote:

quoted

From: Srinivas Pandruvada <srinivas.pandruvada@linux.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.

[ ... ]

quoted

+	[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.

I understand they can be set independently but is the constraint above
correct? For example, can the system send perf=255 and eff=255 or perf=0
and eff=0 ?

May be I misunderstood but I was expecting at least some kind of
connection between perf and eff (when eff is high, perf is low and the
opposite).


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