[v2,5/5] powercap/drivers/dtpm: Scale the power with the load

Message ID 20210309224244.27225-5-daniel.lezcano@linaro.org
State New
Headers show
Series
  • [v2,1/5] powercap/drivers/dtpm: Encapsulate even more the code
Related show

Commit Message

Daniel Lezcano March 9, 2021, 10:42 p.m.
Currently the power consumption is based on the current OPP power
assuming the entire performance domain is fully loaded.

That gives very gross power estimation and we can do much better by
using the load to scale the power consumption.

Use the utilization to normalize and scale the power usage over the
max possible power.

Tested on a rock960 with 2 big CPUS, the power consumption estimation
conforms with the expected one.

Before this change:

~$ ~/dhrystone -t 1 -l 10000&
~$ cat /sys/devices/virtual/powercap/dtpm/dtpm:0/dtpm:0:1/constraint_0_max_power_uw
2260000

After this change:

~$ ~/dhrystone -t 1 -l 10000&
~$ cat /sys/devices/virtual/powercap/dtpm/dtpm:0/dtpm:0:1/constraint_0_max_power_uw
1130000

~$ ~/dhrystone -t 2 -l 10000&
~$ cat /sys/devices/virtual/powercap/dtpm/dtpm:0/dtpm:0:1/constraint_0_max_power_uw
2260000

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

---

V2:
  - Replaced cpumask by em_span_cpus
  - Changed 'util' metrics variable types
  - Optimized utilization scaling power computation
  - Renamed parameter name for scale_pd_power_uw()
---
 drivers/powercap/dtpm_cpu.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

-- 
2.17.1

Comments

kernel test robot March 10, 2021, 12:40 a.m. | #1
Hi Daniel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on pm/linux-next]
[also build test WARNING on linux/master linus/master v5.12-rc2 next-20210309]
[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]

url:    https://github.com/0day-ci/linux/commits/Daniel-Lezcano/powercap-drivers-dtpm-Encapsulate-even-more-the-code/20210310-064505
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: powerpc-randconfig-r005-20210309 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project cd9a69289c7825d54450cb6829fef2c8e0f1963a)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://github.com/0day-ci/linux/commit/195420841883f38897ba1e10ff70641dab0191ba
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Daniel-Lezcano/powercap-drivers-dtpm-Encapsulate-even-more-the-code/20210310-064505
        git checkout 195420841883f38897ba1e10ff70641dab0191ba
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/powercap/dtpm_cpu.c:76:32: warning: variable 'cpu' is uninitialized when used here [-Wuninitialized]

           max = arch_scale_cpu_capacity(cpu);
                                         ^~~
   drivers/powercap/dtpm_cpu.c:74:9: note: initialize the variable 'cpu' to silence this warning
           int cpu;
                  ^
                   = 0
   1 warning generated.


vim +/cpu +76 drivers/powercap/dtpm_cpu.c

    70	
    71	static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
    72	{
    73		unsigned long max, sum_util = 0;
    74		int cpu;
    75	
  > 76		max = arch_scale_cpu_capacity(cpu);

    77	
    78		for_each_cpu_and(cpu, pd_mask, cpu_online_mask)
    79			sum_util += sched_cpu_util(cpu, max);
    80	
    81		return (power * ((sum_util << 10) / max)) >> 10;
    82	}
    83	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Patch

diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c
index ac7f2e7e262f..6a1537e6da0d 100644
--- a/drivers/powercap/dtpm_cpu.c
+++ b/drivers/powercap/dtpm_cpu.c
@@ -68,27 +68,40 @@  static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
 	return power_limit;
 }
 
+static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
+{
+	unsigned long max, sum_util = 0;
+	int cpu;
+
+	max = arch_scale_cpu_capacity(cpu);
+
+	for_each_cpu_and(cpu, pd_mask, cpu_online_mask)
+		sum_util += sched_cpu_util(cpu, max);
+
+	return (power * ((sum_util << 10) / max)) >> 10;
+}
+
 static u64 get_pd_power_uw(struct dtpm *dtpm)
 {
 	struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
 	struct em_perf_domain *pd;
-	struct cpumask cpus;
+	struct cpumask *pd_mask;
 	unsigned long freq;
-	int i, nr_cpus;
+	int i;
 
 	pd = em_cpu_get(dtpm_cpu->cpu);
-	freq = cpufreq_quick_get(dtpm_cpu->cpu);
 
-	cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
-	nr_cpus = cpumask_weight(&cpus);
+	pd_mask = em_span_cpus(pd);
+
+	freq = cpufreq_quick_get(dtpm_cpu->cpu);
 
 	for (i = 0; i < pd->nr_perf_states; i++) {
 
 		if (pd->table[i].frequency < freq)
 			continue;
 
-		return pd->table[i].power *
-			MICROWATT_PER_MILLIWATT * nr_cpus;
+		return scale_pd_power_uw(pd_mask, pd->table[i].power *
+					 MICROWATT_PER_MILLIWATT);
 	}
 
 	return 0;