[PATCH v4 18/18] Documentation: EM: Update information about performance field

From: Lukasz Luba
Date: Mon Sep 25 2023 - 04:12:57 EST


The Energy Model supports the new information: performance for each
performance state. Update the needed documentation part accordingly.

Signed-off-by: Lukasz Luba <lukasz.luba@xxxxxxx>
---
Documentation/power/energy-model.rst | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/Documentation/power/energy-model.rst b/Documentation/power/energy-model.rst
index 3115411f9839..da3619c0b98a 100644
--- a/Documentation/power/energy-model.rst
+++ b/Documentation/power/energy-model.rst
@@ -125,6 +125,11 @@ runtime static EM' (system property) design to a 'single EM which can be
changed during runtime according e.g. to the workload' (system and workload
property) design.

+It is possible also to modify the CPU performance values for each EM's
+performance state. Thus, the full power and performance profile (which
+is an exponential curve) can be changed according e.g. to the workload
+or system property.
+

3. Core APIs
------------
@@ -326,18 +331,18 @@ EM framework::
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This section provides a simple example of a thermal driver modifying the EM.
-The driver implements a foo_mod_power() function to be provided to the
+The driver implements a mod_power_perf() function to be provided to the
EM framework. The driver is woken up periodically to check the temperature
and modify the EM data if needed::

-> drivers/thermal/foo_thermal.c

- 01 static int foo_mod_power(struct device *dev, unsigned long freq,
- 02 unsigned long *power, void *priv)
+ 01 static int mod_power_perf(struct device *dev, unsigned long freq,
+ 02 unsigned long *power, unsigned long *perf, void *priv)
03 {
04 struct foo_context *ctx = priv;
05
- 06 /* Estimate power for the given frequency and temperature */
+ 06 *perf = foo_estimate_performance(dev, freq);
07 *power = foo_estimate_power(dev, freq, ctx->temperature);
08 if (*power >= EM_MAX_POWER);
09 return -EINVAL;
--
2.25.1