Configure CPU, GPU, and memory - Qualcomm Dragonwing Documentation

It’s essential to configure your device’s basic settings before analyzing system performance. The settings play a significant role in the performance of the device. You can configure the CPU, GPU, and memory settings.

Any configuration changes can impact the power and the performance of the device. Ensure that you verify the impact across all relevant use cases before any modifications.

Configure CPU

You can check and modify the CPU configurations using the commands specified in the following table:

The commands specified in the following table should be run on the device. The unit of the output value for these commands is in KHz.

The commands containing policy7 aren’t supported on QCS5430 FP1.

To configure a CPU for Qualcomm Dragonwing^™ IQ-9075 and Qualcomm Dragonwing^™ IQ-8275, see the corresponding addendum:

Table : Commands to configure the CPU for QCS6490, QCS5430 FP2, FP2.5, FP3

Command	Purpose
`cat /sys/devices/system/cpu/online`	Checks the online CPU cores.
`echo 1 > /sys/devices/system/cpu/cpuX/online`	Turns on a CPU core. In cpuX, X represents the number of cores, which ranges from 0 to 7.
`echo 0 > /sys/devices/system/cpu/cpuX/online`	Turns off a CPU core. In cpuX, X represents the number of cores, which ranges from 0 to 7.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq` `cat /sys/devices/system/cpu/cpufreq/policy4/scaling_cur_freq` `cat /sys/devices/system/cpu/cpufreq/policy7/scaling_cur_freq`	Reads the current CPU frequency.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies` `cat /sys/devices/system/cpu/cpufreq/policy4/scaling_available_frequencies` `cat /sys/devices/system/cpu/cpufreq/policy7/scaling_available_frequencies`	Reads the supported CPU frequencies.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq` `cat /sys/devices/system/cpu/cpufreq/policy4/scaling_min_freq` `cat /sys/devices/system/cpu/cpufreq/policy7/scaling_min_freq`	Reads the minimum CPU frequency.
`echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq` `echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy4/scaling_min_freq` `echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy7/scaling_min_freq`	Sets the minimum CPU frequency. Replace `<cpu freq in KHz>` with the required frequency and run the commands.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq` `cat /sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq` `cat /sys/devices/system/cpu/cpufreq/policy7/scaling_max_freq`	Reads the maximum CPU frequency.
`echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq` `echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq` `echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy7/scaling_max_freq`	Sets the maximum CPU frequency. Replace `<cpu freq in KHz>` with the required frequency and run the commands.
`cat /sys/devices/system/cpu/cpufreq/policy0/stats/trans_table` `cat /sys/devices/system/cpu/cpufreq/policy4/stats/trans_table` `cat /sys/devices/system/cpu/cpufreq/policy7/stats/trans_table`	Checks the CPU residency.
For example, to set the CPU frequency of the Silver core at 1.5 GHz, run the following commands: `echo 1516800 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq` `echo 1516800 > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq`	Sets the CPU frequency. Set `scaling_min_freq` and `scaling_max_freq` to the same frequency to keep the CPU frequency at the required level.

You can check and modify the CPU configurations for Qualcomm Dragonwing^™ IQ-615 using the commands specified in the following table: Table : Commands to configure the CPU for Dragonwing IQ-615

Command	Purpose
`cat /sys/devices/system/cpu/online`	Checks the online CPU cores.
`echo 1 > /sys/devices/system/cpu/cpuX/online`	Turns on a CPU core. In cpuX, X represents the number of cores, which ranges from 0 to 7.
`echo 0 > /sys/devices/system/cpu/cpuX/online`	Turns off a CPU core. In cpuX, X represents the number of cores, which ranges from 0 to 7.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq` `cat /sys/devices/system/cpu/cpufreq/policy6/scaling_cur_freq`	Reads the current frequency of the CPU.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies` `cat /sys/devices/system/cpu/cpufreq/policy6/scaling_available_frequencies`	Reads the supported frequencies of the CPU.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq` `cat /sys/devices/system/cpu/cpufreq/policy6/scaling_min_freq`	Reads the minimum frequency of the CPU.
`echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq` `echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy6/scaling_min_freq`	Sets the minimum frequency of the CPU. Replace `<cpu freq in KHz>` with the required frequency and run the commands.
`cat /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq` `cat /sys/devices/system/cpu/cpufreq/policy6/scaling_max_freq`	Reads the maximum frequency of the CPU.
`echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq` `echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy6/scaling_max_freq`	To set the maximum frequency of the CPU, replace `<cpu freq in KHz>` with the required frequency and run the commands.
`cat /sys/devices/system/cpu/cpufreq/policy0/stats/trans_table` `cat /sys/devices/system/cpu/cpufreq/policy6/stats/trans_table`	Checks the CPU residency.
For example, to set the CPU frequency of the Silver core at 1.5 GHz, run the following commands: `echo 1516800 > /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq` `echo 1516800 > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq`	To set the CPU frequency at a required level, both `scaling_min_freq` and `scaling_max_freq` should be set to the same frequency.

Configure GPU

You can check and modify the GPU configurations on the device using the commands specified in the following table:

The commands specified in the following table should be run on the device. The unit of the output value for these commands is in Hz.

Table : Commands to configure the GPU

Command	Purpose
`cat /sys/class/kgsl/kgsl-3d0/gpuclk`	Reads the current GPU frequency.
`cat /sys/class/kgsl/kgsl-3d0/gpu_available_frequencies`	Reads the supported GPU frequencies.
`cat /sys/class/kgsl/kgsl-3d0/devfreq/min_freq`	Reads the minimum GPU frequency.
`echo <GPU freq in Hz> > /sys/class/kgsl/kgsl-3d0/devfreq/min_freq`	Sets the minimum GPU frequency. Replace `<GPU freq in Hz>` with the required frequency in Hz and run the command.
`cat /sys/class/kgsl/kgsl-3d0/devfreq/max_freq`	Reads the maximum GPU frequency.
`echo <GPU freq in Hz> /sys/class/kgsl/kgsl-3d0/devfreq/max_freq`	Sets the maximum GPU frequency. Replace `<GPU freq in Hz>` with the required frequency in Hz and run the command.
`cat /sys/class/kgsl/kgsl-3d0/gpu_busy_percentage`	Reads the GPU percentage usage.
For example, to set the GPU frequency at 600000000 Hz, run the following commands: `echo 600000000 > /sys/class/kgsl/kgsl-3d0/devfreq/min_freq` `echo 600000000 > /sys/class/kgsl/kgsl-3d0/devfreq/max_freq`	Sets the GPU frequency at a required level; both `min_freq` and `max_freq` should be set to the same frequency level.
`cat /sys/class/kgsl/kgsl-3d0/max_pwrlevel` `cat /sys/class/kgsl/kgsl-3d0/min_pwrlevel`	Reads the GPU power levels. Power level 0 corresponds to the maximum GPU clock frequency. As the power level value increases, the GPU clock frequency decreases.
`echo 0 > /sys/class/kgsl/kgsl-3d0/min_pwrlevel`	Sets the GPU frequency to maximum frequency.

Configure memory

Memory configuration is crucial to conserve memory, make space available for processes, and balance the existing data in RAM when the physical memory reaches its limits.

Set ZRAM disk size

ZRAM is a RAM partition to swap memory space. It stores the inactive anonymous pages in a compressed form in RAM to conserve memory. The ZRAM disk size indicates the maximum amount of memory that can be swapped from RAM to ZRAM. It’s recommended to set the ZRAM disk size to half the size of RAM. ZRAM is enabled by default in the Qualcomm^® Linux^® build. By default, 50% of RAM is configured as the ZRAM memory limit using the /sys/block/zram*/mem_limit parameter in the post_boot_common.sh script. To reconfigure the ZRAM memory limit, modify the /sys/block/zram*/mem_limit parameter value in the post_boot_common.sh script located at /etc/urm/initscripts/post_boot/ on the device. For more information about the post-boot scripts, see Post-boot init scripts.

Enable/disable proactive compaction

Compaction is a process that collects all the free memory spaces in the form of fragments into a large memory block. Proactive compaction determines the level of aggressiveness with which memory compaction happens in the background. It accepts a value between 0 and 100, with the default value set to 20. When the fragmentation score of the node exceeds a high threshold, the corresponding kcompactd thread initiates the proactive compaction process. The compaction process remains active until the score of the node falls below the low threshold. The thresholds for proactive compaction are as follows:

Low = 100 - proactiveness
High = low + 10%

For instance, if the low threshold is 80, the high threshold would be 90. To enable proactive compaction, run the following command on the device:

echo 20 > /proc/sys/vm/compaction_proactiveness

To disable proactive compaction, which also turns off the periodic kcompactd wake-ups, run the following command on the device:

echo 0 > /proc/sys/vm/compaction_proactiveness

For more information, see Proactive compaction for the kernel.

Swappiness

Swap space is a secondary storage that functions similar to the main memory or RAM. The primary parameter of swap space is swappiness.

This parameter determines how aggressively the kernel swap daemon (kswapd) swaps out anonymous memory relative to the system page cache.
This parameter can take a value between 0 and 200. Increasing the value augments the amount of anonymous swapping. The configured value is 100, indicating that both anonymous and cache memories are reclaimed equally.

To adjust the swappiness value, run the following command on the device:

echo 100 > /proc/sys/vm/swappiness

For more information about memory parameters, see Documentation for /proc/sys/vm/.

Next steps

Customize for performance tuning

​Configure CPU

​Configure GPU

​Configure memory

​Set ZRAM disk size

​Enable/disable proactive compaction

​Swappiness

​Next steps

Configure CPU

Configure GPU

Configure memory

Set ZRAM disk size

Enable/disable proactive compaction

Swappiness

Next steps