# Customize for performance tuning Customization is a process that includes fine-tuning various aspects of the system, which can significantly affect the overall performance and power of the system. The CPU scheduler, CPU frequency governor, dynamic voltage and frequency scaling (DVFS) governor, perflock, and memory can be fine-tuned. It's recommended to undertake any tuning only after gaining a thorough understanding through extensive performance and power analysis. Caution Any customization can impact the power and the performance of the device. Therefore, it's crucial to verify the impact across all the relevant use cases before performing any customization. ## Customize CPU scheduler You can customize features of the CPU scheduler, such as utilization clamping (UCLAMP or util clamp) schedulers. For more information, see [CPU scheduler](https://docs.qualcomm.com/doc/80-70020-10/topic/2-performance-features.html#cpu-scheduler). ### UCLAMP UCLAMP is a scheduler feature that allows user space to manage the task performance requirements. It's a hinting mechanism that helps the scheduler understand the performance demands and limitations of tasks, as a result, it assists the scheduler in making informed decisions. When the `schedutil` CPU frequency governor is used, UCLAMP determines the CPU frequency selection. The UCLAMP value ranges from 0 to 1024. The following parameters can be customized for UCLAMP: - `sched_util_clamp_min`: This parameter sets the minimum acceptable performance level for individual tasks and task groups, ensuring that tasks receive sufficient resources to operate effectively, even during periods of low demand. Any requested `uclamp.min` value for a task can't exceed `sched_util_clamp_min`. - For the scheduler, it acts as a lower bound on the per entity load tracking (PELT) signal, which tracks task usage. - For the CPU frequency, it instructs the governor to select a frequency that can meet the performance requirements of the task, thus ensuring responsiveness and efficiency. The Qualcomm-tuned value is 1024. To set this parameter, run the following command on the device: echo 1024 > /proc/sys/kernel/sched_util_clamp_min Copy to clipboard - `sched_util_clamp_max`: This parameter sets the maximum acceptable performance level for individual tasks and task groups. It ensures that tasks don't consume excessive resources, preventing resource contention and system instability. Any requested `uclamp.max` value for a task can't exceed `sched_util_clamp_max`. - For the scheduler, it acts as a ceiling on the PELT signal, which tracks the task usage. - For the CPU frequency, if the task demands exceed the available frequency, the governor may adjust the frequency to prevent excessive power consumption. The Qualcomm-tuned value is 1024. To set this parameter, run the following command on the device: echo 1024 > /proc/sys/kernel/sched_util_clamp_max Copy to clipboard - `sched_util_clamp_min_rt_default`: By default, the real-time (RT) tasks always run at the highest frequency and highest CPU capacity. This parameter allows you to change the default behavior of an RT task when UCLAMP is being used. It allows tuning the best value for an RT task, offering good performance without pushing it to the maximum performance point. This behavior addresses the system requirement without burning power and running at the maximum performance point all the time. The Qualcomm-tuned value is 128. To set this parameter, run the following command on the device: echo 128 > /proc/sys/kernel/sched_util_clamp_min_rt_default Copy to clipboard For more information, see [Utilization Clamping](https://docs.kernel.org/scheduler/sched-util-clamp.html). ## Customize CPU frequency governor You can configure a CPU frequency governor using the `scaling_governor` node to enhance CPU performance. Note The commands containing `policy7` aren't supported on QCS5430 FP1. To customize a frequency governor for Qualcomm Dragonwing^™^ IQ-9075, Qualcomm Dragonwing^™^ IQ-8275, and Qualcomm Dragonwing^™^ IQ-615, see the corresponding addendum. The following guides are available to licensed users with authorized access: - [Qualcomm Linux Performance Guide - Addendum for Qualcomm Dragonwing IQ-9075](https://docs.qualcomm.com/bundle/resource/topics/80-70020-10A/overview.html) - [Qualcomm Linux Performance Guide - Addendum for Qualcomm Dragonwing IQ-8275](https://docs.qualcomm.com/bundle/resource/topics/80-70020-10B/overview.html) - [Qualcomm Linux Performance Guide - Addendum for Qualcomm Dragonwing IQ-615](https://docs.qualcomm.com/bundle/resource/topics/80-70020-10C/overview.html) Note The commands specified in the following table should be run on the device. Table : Commands to customize the CPU frequency governor | Command | Purpose | | --- | --- | | echo performance > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
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echo performance > /sys/devices/system/cpu/cpufreq/policy4/scaling_governor
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echo performance > /sys/devices/system/cpu/cpufreq/policy7/scaling_governor
Copy to clipboard | Sets the CPU governor to enhance the system performance. | | cat /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
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cat /sys/devices/system/cpu/cpufreq/policy4/scaling_governor
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cat /sys/devices/system/cpu/cpufreq/policy7/scaling_governor
Copy to clipboard | Verifies the CPU frequency governor. | | echo schedutil > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
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echo schedutil > /sys/devices/system/cpu/cpufreq/policy4/scaling_governor
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echo schedutil > /sys/devices/system/cpu/cpufreq/policy7/scaling_governor
Copy to clipboard | Sets the CPU frequency governor to `schedutil`. | | echo 1000 > /sys/devices/system/cpu/cpufreq/policyX/schedutil/rate_limit_us
Copy to clipboard | Customizes `rate_limit_us`.


The value of `X` in `policyX` corresponds to clusters 0,
4, and 7.


This is a `schedutil` governor parameter. It contains the
value in microseconds. The governor waits for
`rate_limit_us` time to re-evaluate the load. The Qualcomm-tuned value is 1000. | ## Customize DVFS governor You can customize the static map DVFS governor and bandwidth monitoring (BWMON) governor using DTSI files according to both the power and the performance requirements of your device. ### Customize static map DVFS governor You can customize the mapping between the CPU frequency and the L3/DDR frequency according to both, the power and the performance requirements from the `arch/arm64/boot/dts/qcom/.dtsi` file in the source code. In the DTSI file, for each CPU node, there is an entry with `operating-points-v2 = <&cpux_opp_table>`, where `cpux_opp_table` holds the static mapping between the CPU frequency, and the L3 and the DDR frequencies. For example, the following entry indicates that the CPU 0 frequency operates at 300 MHz: cpu0_opp_300mhz: opp-300000000 { opp-hz = /bits/ 64 <300000000>; pp-peak-kBps = <800000 9600000>; }; Copy to clipboard When CPU 0 operates at 300 MHz, it performs the following actions: - Votes L3 to 9600000, which is 9600000/w (where w = 32) = 300,000, which corresponds to 300 MHz - Votes DDR to 800000, which is 800000/w (where w = 4) = 200,00, which corresponds to 200 MHz In this example, 'w' represents the number of bytes you can write in a single cycle. - For L3, this value is 32, which means one transaction per cycle at 32 bytes per transaction. - For dual-channel DDR, this value is 4. Each channel can perform two transactions per cycle (because it's the DDR memory), and each transaction is of 2 bytes. For more information, see [Generic OPP (Operating Performance Points) Bindings](https://www.kernel.org/doc/Documentation/devicetree/bindings/opp/opp.txt). The tables specify the per channel DDR values. This implies that the mapping is between the CPU frequency and the bandwidth of each memory controller channel. Caution If you change the DTSI files, it impacts the power and the performance of the device. Ensure that you verify the impact across all the relevant use cases before changing any nodes. ### Customize BWMON governor You can customize `bwmon_opp_table` for the last level cache controller (LLCC) and DDR voting according to both the power and the performance requirements from the `arch/arm64/boot/dts/qcom/.dtsi` file in the source code. The following code samples contain the DDR frequency level and the LLCC frequency level, and each level translates to LLCC and DDR voting based on the traffic. The following DTSI entry votes to DDR based on the CPU traffic between LLCC to DDR, which corresponds to 200 MHz. In this example, 800000/w (where w = 4) equals 200000: llcc_bwmon_opp_table: opp-table { compatible = "operating-points-v2"; opp-0 { opp-peak-kBps = <800000>; }; Copy to clipboard The following DTSI entry votes to LLCC based on the CPU traffic between CPU and LLCC, which corresponds to 150 MHz. In this example, 2400000/w (where w = 16) equals 150000: cpu_bwmon_opp_table: opp-table { compatible = "operating-points-v2"; opp-0 { opp-peak-kBps = <2400000>; }; Copy to clipboard In these examples, 'w' represents the number of bytes that you can write in a single cycle. - For DDR, this value is 4. Each channel can perform two transactions per cycle (DDR memory), and each transaction is of 2 bytes. - For LLCC, this value is 16. ## Customize perflock You can use perflock APIs, run a use case using different tuning parameters, and debug the perflock issues. ### Perflock APIs To use the perflock APIs from the user space source code, do the following: 1. Include a dynamic linking header in the source file: `#include `. 2. Load `library(libqti-perfd-client.so)` using `dlopen`. 3. Load the `perf_lock_acq()` and `perf_lock_rel()` symbols using `dlsym`. 4. Declare an integer variable to store the returns of `perf_lock_acq()`. 5. Define `perf_lock_opts` with the required resource opcode and value pairs. 6. Acquire a lock with the specified optimizations using `perf_lock_acq()`. 7. Release the lock using `perf_lock_rel()`. 8. Unload the library using `dlclose` on cleanup. The following sample code shows the usage of perflock APIs and illustrates how to set the minimum frequency of the Silver core to 1.9 GHz: #include #include #include #include #include #define PATH_MAX 92 static void *qcopt_handle; static int (*perf_lock_acq)(int handle, int duration, int list[], int numArgs); static int (*perf_lock_rel)(int handle); static int perf_lock_handle; char opt_lib_path[PATH_MAX] = "/usr/lib/libqti-perfd-client.so"; int main() { if ((qcopt_handle = dlopen(opt_lib_path, RTLD_NOW)) == NULL) { printf("dlopen failed with error: NULL\n"); } else { printf("call perflock \n"); perf_lock_acq = (int (*)(int, int, int *, int))dlsym(qcopt_handle, "perf_lock_acq"); if(!perf_lock_acq) printf("Unable to get perf_lock_rel function handle.\n"); perf_lock_rel = (int (*)(int))dlsym(qcopt_handle, "perf_lock_rel"); } int perf_lock_opts[2] = {0x44008100,1958400}; perf_lock_handle = perf_lock_acq(perf_lock_handle, 0, perf_lock_opts, 2); printf("perflock acquired %d\n", perf_lock_handle); //Code section requiring perflock perf_lock_rel(perf_lock_handle); printf("releasing perflock\n"); dlclose(qcopt_handle); return 0; } Copy to clipboard ### Perflock native test The perflock native test is a tool designed to evaluate the effectiveness of specific combinations of perflock opcodes. This tool is available at `/usr/bin/` on the device. You can run this utility as a use case to experiment with different tuning parameters for ``. When the required performance improvements are confirmed, the perflock code can be integrated into Qualcomm^®^ Linux^®^. The following code shows the syntax: perflock_native_test --acq Copy to clipboard The following are some examples of how to use the tool. Run these commands on the device: - To acquire a perflock for the Silver cluster with minimum frequency set to 1958400 KHz for 30 seconds, run the following command: perflock_native_test --acq 0 30000 0x44008100,1958400 Copy to clipboard - To verify the minimum frequency of the Silver cluster, run the following command: cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq Copy to clipboard - To verify the perflock logging from `syslog`, run the following command: cat /var/log/syslog Copy to clipboard The following are the logs: perflock\_native\_test: ANDR-PERFLOCK-TESTERANDR-PERFLOCK-TESTER: initialize() 60: NRP: lib name libqti-perfd-client.so perflock\_native\_test: ANDR-PERFLOCK-TESTERANDR-PERFLOCK-TESTER: main() 502: NRP: resource\_list[0] = 44008100 //silver core min frequency opcode perflock\_native\_test: ANDR-PERFLOCK-TESTERANDR-PERFLOCK-TESTER: main() 502: NRP: resource\_list[1] = 7a6 // silver core min freq in hex ### Debug perflock The following are some examples of logging mechanisms to debug the perflock issues: Note The following example commands should be run on the device. - To verify if the PerfHAL service is available, run the following command: ls /usr/bin | grep perf Copy to clipboard - To verify the running status of the PerfHAL service, run the following command: systemctl status perf-hal Copy to clipboard - To enable perflock logs and traces in `/var/log/syslog`, run the following commands: echo debug.trace.perf=1 >> /etc/build.prop Copy to clipboard echo vendor.debug.trace.perf=1 >> /etc/build.prop Copy to clipboard reboot Copy to clipboard ## Customize memory You can manage virtual memory using Kswapd, regulate system memory using watermark, and define memory regions for specific subsystems through memory carveouts. ### Kswapd Kswapd is a kernel thread that manages the virtual memory. When the system is low on free memory, Kswapd is activated to reclaim memory by identifying less frequently used pages from the file cache and moving them to the swap space (ZRAM). Kswapd does the following: - Monitors the memory usage of the system - Performs swapping activities in the background to maintain an optimal level of free memory ![../../_images/cpu_usage_performance_using_kswapd.png](data:image/png;base64,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) **Figure : CPU usage vs. performance using Kswapd** ### Watermark A watermark is a threshold or limit set on memory parameters that helps regulate the allocation and usage of system memory. Table : Watermark parameters | Parameter | Description | | --- | --- | | `/proc/sys/vm/min_free_kbytes` |

  • This parameter determines the minimum amount of free
    memory that the system must maintain across all zones.


  • It ensures that a certain reserve of memory remains
    available for critical operations, such as handling
    atomic allocations, which can't wait for memory
    reclamation.


  • The number of reserved free pages in each zone is
    proportional to its size.


| | `/proc/sys/vm/watermark_scale_factor` |

  • This factor controls the aggressiveness of Kswapd.


  • It defines the amount of memory left in a system before
    Kswapd is woken up, and the amount of free memory
    required before Kswapd goes back to sleep.


  • The unit is in fractions of 10,000.


  • The default value of 10 means that the distance between
    the watermarks is 0.1% of the available memory in the
    node or system. The maximum value is 1000, or 10% of
    memory.


| | `/proc/sys/vm/watermark_boost_factor` |

  • This factor is used to optimize memory fragmentation by
    temporarily providing a high-watermark for the memory
    management area, which allows Kswapd to reclaim more
    memory.


  • The unit is in fractions of 10,000.


  • The default value of 15,000 means that up to 150% of the
    high watermark is reclaimed in the event of a pageblock
    being mixed due to fragmentation.


  • The number of fragmentation events that have occurred in
    the recent past determine the level of reclaim. A boost
    factor of 0 disables the feature.


| For more information, see [Documentation for /proc/sys/vm/](https://www.kernel.org/doc/Documentation/admin-guide/sysctl/vm.rst). ### Memory carveout Memory carveouts refer to specific memory regions that the kernel can't address, known as no-map regions. Specific subsystems such as modem, camera, aDSP, cDSP, and Qualcomm^®^ Trusted Execution Environment (TEE)/TrustZone (TZ) use these regions exclusively and hence those are inaccessible to the Linux kernel. These carveouts are defined in the source code at `arch/arm64/boot/dts/qcom/.dtsi`. They fall under the `reserved-memory` node and can be configured. The following code shows the no-map regions for the cDSP, camera, modem, and QTEE/TrustZone (TZ) subsystems: reserved-memory { cdsp_secure_heap_mem: cdsp-secure-heap@81800000 { reg = <0x0 0x81800000 0x0 0x1e00000>; no-map; }; camera_mem: camera@84300000 { reg = <0x0 0x84300000 0x0 0x500000>; no-map; }; adsp_mem: adsp@86100000 { reg = <0x0 0x86100000 0x0 0x2800000>; no-map; }; cdsp_mem: cdsp@88900000 { reg = <0x0 0x88900000 0x0 0x1e00000>; no-map; }; mpss_mem: mpss@8b800000 { reg = <0x0 0x8b800000 0x0 0xf600000>; no-map; }; tz_stat_mem: tz-stat@c0000000 { reg = <0x0 0xc0000000 0x0 0x100000>; no-map; }; tags_mem: tags@c0100000 { reg = <0x0 0xc0100000 0x0 0x1200000>; no-map; }; Copy to clipboard You can adjust the reserved memory carveout regions based on your product requirements. This adjustment can include removing a modem carveout region or reducing the size of QTEE/TrustZone (TZ) application memory carveout regions. For example, the following code snippet shows how to disable the modem memory carveout for memory optimization: reserved-memory { mpss_mem: mpss@8b800000 { reg = <0x0 0x8b800000 0x0 0xf600000>; no-map; status = "disabled"; }; Copy to clipboard In this code: - `0x8b800000` is the base address of the modem region. - `0xf600000` is the size of the modem region, which is 246 MB. - Add `status = disabled` to make this region available to the Linux kernel. The following example snippets show how to reduce the memory carveout size of the QTEE/TrustZone (TZ) applications from 28 MB (`0x1c00000`) to 20 MB (`0x1400000`): | - Before:
- reserved memory {
trusted_apps_mem: trusted_apps@c1800000 {
reg = <0x0 0xc1800000 0x0 0x1c00000>;
no-map;
};
Copy to clipboard | - After:
- reserved memory {
trusted_apps_mem: trusted_apps@c1800000 {
reg = <0x0 0xc1800000 0x0 0x1400000>;
no-map;
};
Copy to clipboard | | --- | --- | ## Next steps - [Troubleshoot performance issues](https://docs.qualcomm.com/doc/80-70020-10/topic/24-debug.html#debug) Last Published: Jul 08, 2025 [Previous Topic Configure CPU, GPU, and memory](https://docs.qualcomm.com/bundle/publicresource/80-70020-10/topics/14-configure.md) [Next Topic Troubleshoot performance issues](https://docs.qualcomm.com/bundle/publicresource/80-70020-10/topics/24-debug.md)