Hi all,
This is a follow-up patch aiming to add EM modification due to chip binning.
The first RFC and the discussion can be found here [1].
It uses Exynos chip driver code as a 1st user. The EM framework has been
extended to handle this use case easily, when the voltage has been changed
after setup. On my Odroid-xu4 in some OPPs I can observe ~20% power difference.
According to that data in driver tables it could be up to ~29%.
This chip binning is applicable to a lot of SoCs, so the EM framework should
make it easy to update. It uses the existing OPP and DT information to
re-calculate the new power values.
It has dependency on Exynos SoC driver.
Changes:
v3:
- updated header description patch 2/4 (Dietmar)
- removed 2 sentences from comment and adjusted in patch 3/4 (Dietmar)
- patch 4/4 re-phrased code comment (Dietmar)
- collected tags (Krzysztof, Viresh)
v2:
- removed 'ret' from error message which wasn't initialized (Christian)
v1:
- exported the OPP calculation function from the OPP/OF so it can be
used from EM fwk (Viresh)
- refactored EM updating function to re-use common code
- added new EM function which can be used by chip device drivers which
modify the voltage in OPPs
RFC is at [1]
Regards,
Lukasz Luba
Lukasz Luba (4):
OPP: OF: Export dev_opp_pm_calc_power() for usage from EM
PM: EM: Change the em_adjust_new_capacity() to re-use code
PM: EM: Add em_dev_update_chip_binning()
soc: samsung: exynos-asv: Update Energy Model after adjusting voltage
drivers/opp/of.c | 17 +++--
drivers/soc/samsung/exynos-asv.c | 11 +++-
include/linux/energy_model.h | 5 ++
include/linux/pm_opp.h | 8 +++
kernel/power/energy_model.c | 106 +++++++++++++++++++++++++------
5 files changed, 122 insertions(+), 25 deletions(-)
--
2.25.1
Add a function which allows to modify easily the EM after the new voltage
information is available. The device drivers for the chip can adjust
the voltage values after setup. The voltage for the same frequency in OPP
can be different due to chip binning. The voltage impacts the power usage
and the EM power values can be updated to reflect that.
Signed-off-by: Lukasz Luba <[email protected]>
---
include/linux/energy_model.h | 5 ++++
kernel/power/energy_model.c | 48 ++++++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index 770755df852f1..d30d67c2f07cf 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -172,6 +172,7 @@ struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd);
void em_table_free(struct em_perf_table __rcu *table);
int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
int nr_states);
+int em_dev_update_chip_binning(struct device *dev);
/**
* em_pd_get_efficient_state() - Get an efficient performance state from the EM
@@ -387,6 +388,10 @@ int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
{
return -EINVAL;
}
+static inline int em_dev_update_chip_binning(struct device *dev)
+{
+ return -EINVAL;
+}
#endif
#endif
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index 6960dd7393b2d..e284aa335b6d0 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -808,3 +808,51 @@ static void em_update_workfn(struct work_struct *work)
{
em_check_capacity_update();
}
+
+/**
+ * em_dev_update_chip_binning() - Update Energy Model after the new voltage
+ information is present in the OPPs.
+ * @dev : Device for which the Energy Model has to be updated.
+ *
+ * This function allows to update easily the EM with new values available in
+ * the OPP framework and DT. It can be used after the chip has been properly
+ * verified by device drivers and the voltages adjusted for the 'chip binning'.
+ */
+int em_dev_update_chip_binning(struct device *dev)
+{
+ struct em_perf_table __rcu *em_table;
+ struct em_perf_domain *pd;
+ int i, ret;
+
+ if (IS_ERR_OR_NULL(dev))
+ return -EINVAL;
+
+ pd = em_pd_get(dev);
+ if (!pd) {
+ dev_warn(dev, "Couldn't find Energy Model\n");
+ return -EINVAL;
+ }
+
+ em_table = em_table_dup(pd);
+ if (!em_table) {
+ dev_warn(dev, "EM: allocation failed\n");
+ return -ENOMEM;
+ }
+
+ /* Update power values which might change due to new voltage in OPPs */
+ for (i = 0; i < pd->nr_perf_states; i++) {
+ unsigned long freq = em_table->state[i].frequency;
+ unsigned long power;
+
+ ret = dev_pm_opp_calc_power(dev, &power, &freq);
+ if (ret) {
+ em_table_free(em_table);
+ return ret;
+ }
+
+ em_table->state[i].power = power;
+ }
+
+ return em_recalc_and_update(dev, pd, em_table);
+}
+EXPORT_SYMBOL_GPL(em_dev_update_chip_binning);
--
2.25.1
When the voltage for OPPs is adjusted there is a need to also update
Energy Model framework. The EM data contains power values which depend
on voltage values. The EM structure is used for thermal (IPA governor)
and in scheduler task placement (EAS) so it should reflect the real HW
model as best as possible to operate properly.
Based on data on Exynos5422 ASV tables the maximum power difference might
be ~29%. An Odroid-XU4 (with a random sample SoC in this chip lottery)
showed power difference for some OPPs ~20%. Therefore, it's worth to
update the EM.
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
---
drivers/soc/samsung/exynos-asv.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index d60af8acc3916..d6d003e3a81ab 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -11,6 +11,7 @@
#include <linux/cpu.h>
#include <linux/device.h>
+#include <linux/energy_model.h>
#include <linux/errno.h>
#include <linux/of.h>
#include <linux/pm_opp.h>
@@ -97,9 +98,17 @@ static int exynos_asv_update_opps(struct exynos_asv *asv)
last_opp_table = opp_table;
ret = exynos_asv_update_cpu_opps(asv, cpu);
- if (ret < 0)
+ if (!ret) {
+ /*
+ * When the voltage for OPPs could be changed,
+ * make sure to update the EM power values, to
+ * reflect the reality and not use stale data.
+ */
+ em_dev_update_chip_binning(cpu);
+ } else {
dev_err(asv->dev, "Couldn't udate OPPs for cpu%d\n",
cpuid);
+ }
}
dev_pm_opp_put_opp_table(opp_table);
--
2.25.1
Hi Lukasz,
kernel test robot noticed the following build warnings:
[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on krzk/for-next clk/clk-next linus/master v6.9-rc1 next-20240328]
[cannot apply to soc/for-next rafael-pm/acpi-bus rafael-pm/devprop]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Lukasz-Luba/OPP-OF-Export-dev_opp_pm_calc_power-for-usage-from-EM/20240328-165357
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link: https://lore.kernel.org/r/20240328085112.3873050-4-lukasz.luba%40arm.com
patch subject: [PATCH v3 3/4] PM: EM: Add em_dev_update_chip_binning()
config: i386-buildonly-randconfig-002-20240328 (https://download.01.org/0day-ci/archive/20240329/[email protected]/config)
compiler: gcc-12 (Ubuntu 12.3.0-9ubuntu2) 12.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240329/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
>> kernel/power/energy_model.c:814: warning: bad line: information is present in the OPPs.
vim +814 kernel/power/energy_model.c
811
812 /**
813 * em_dev_update_chip_binning() - Update Energy Model after the new voltage
> 814 information is present in the OPPs.
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki