[android-porting] Why almost all of tasks are assigned to core 0, while the others are always idle?

[Alan]

We ported android-7.1.2_r36 to our platform LS1046ARDB which has 4
Cortex-A72 cores, plus a NVIDIA GeForce GTX750 Ti video card. The android
works fine, but when testing its performance with Antutu, we found that the
score value of multi-core is almost the same as the one for single-core.

By adding the mpstat tool to android, it is found that almost all of tasks
are assigned to core 0, while the other cores are always idle, as below:

13:41:56 CPU %usr %nice %sys %iowait %irq %soft %steal
%guest %gnice %idle

13:41:57 all 24.81 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 75.19

13:41:57 0 100.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00

13:41:57 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 100.00

13:41:57 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 100.00

13:41:57 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 100.00


13:41:57 CPU %usr %nice %sys %iowait %irq %soft %steal
%guest %gnice %idle

13:41:58 all 17.25 0.00 0.50 0.00 0.00 0.00 0.00
0.00 0.00 82.25

13:41:58 0 69.00 0.00 1.00 0.00 0.00 0.00 0.00
0.00 0.00 30.00

13:41:58 1 0.00 0.00 1.00 0.00 0.00 0.00 0.00
0.00 0.00 99.00

13:41:58 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 100.00

13:41:58 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 100.00


Attached is the Makefiles used to build the android for our platform.


Does anyone know what we are missing?

Thank you.

[Alan]

The issue is found and fixed. By default, android aosp initially constrain
scheduling to only core 0 with CPU Cgroup function, the others are not
allowed. When porting android asop to our platform, we did not change this
correspondingly according to our platform. By changing the relevant files
under /dev/cpuset in our platform, the issue is fixed.

Cheers!

Post by Alan
We ported android-7.1.2_r36 to our platform LS1046ARDB which has 4
Cortex-A72 cores, plus a NVIDIA GeForce GTX750 Ti video card. The android
works fine, but when testing its performance with Antutu, we found that the
score value of multi-core is almost the same as the one for single-core.
By adding the mpstat tool to android, it is found that almost all of tasks
13:41:56 CPU %usr %nice %sys %iowait %irq %soft %steal
%guest %gnice %idle
13:41:57 all 24.81 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 75.19
13:41:57 0 100.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00
13:41:57 1 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 100.00
13:41:57 2 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 100.00
13:41:57 3 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 100.00
13:41:57 CPU %usr %nice %sys %iowait %irq %soft %steal
%guest %gnice %idle
13:41:58 all 17.25 0.00 0.50 0.00 0.00 0.00
0.00 0.00 0.00 82.25
13:41:58 0 69.00 0.00 1.00 0.00 0.00 0.00
0.00 0.00 0.00 30.00
13:41:58 1 0.00 0.00 1.00 0.00 0.00 0.00
0.00 0.00 0.00 99.00
13:41:58 2 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 100.00
13:41:58 3 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 100.00
Attached is the Makefiles used to build the android for our platform.
Does anyone know what we are missing?
Thank you.