1# CPUP 2 3 4## Basic Concepts 5 6The central processing unit percent (CPUP) includes the system CPUP and task CPUP. 7 8**System CPUP** 9 10The system CPUP is the CPU usage of the system within a period of time. It reflects the CPU load and the system running status (idle or busy) in the given period of time. The CPUP ranges from 0 to 100, in percentage. The value **100** indicates that the system runs with full load. 11 12With the system CPUP, you can determine whether the current system load exceeds the designed specifications. 13 14**Task CPUP** 15 16Task CPUP refers to the CPU usage of a single task. It reflects the task status, busy or idle, in a period of time. The task CPUP ranges from 0 to 100, in percentage. The value **100** indicates that the task is being executed for the given period of time. 17 18With the CPUP of each task, you can determine whether the CPU usage of each task meets expectations of the design. 19 20**Interrupt CPUP** 21 22In addition, you can enable the interrupt usage statistics function after the CPUP function is enabled. 23 24Interrupt CPUP indicates the CPU usage of a single interrupt out of the total interrupt duration. The interrupt CPUP ranges from 0 to 100. The value **100** indicates that only the interrupt is triggered within a period of time. 25 26 27## Working Principles 28 29The OpenHarmony LiteOS-M CPUP records the system CPU usage on a task basis. When task switching occurs, the task start time and task switch-out or exit time are recorded. Each time when a task exits, the system accumulates the CPU time used by the task. 30 31You can configure this function in **target_config.h**. 32 33The OpenHarmony LiteOS-M provides the following types of CPUP information: 34 35- System CPUP 36- Task CPUP 37 38In addition, the system provides the capability of querying the interrupt CPUP (the CPUP and timer must be enabled). 39 40The CPUP is calculated as follows: 41 42System CPUP = Total running time of all tasks except idle tasks/Total running time of the system 43 44Task CPUP = Total running time of the task/Total running time of the system 45 46Interrupt CPUP = Running time of a single interrupt/Total running time of all interrupts 47 48 49## Available APIs 50 51 **Table 1** APIs for CPUP 52 53| Category| Description| 54| -------- | -------- | 55| Obtaining the system CPUP| **LOS_SysCpuUsage**: obtains the current system CPUP.<br>**LOS_HistorySysCpuUsage**: obtains the historical CPUP of the system.| 56| Obtaining the task CPUP| **LOS_TaskCpuUsage**: obtains the CPUP of a task.<br>**LOS_HistoryTaskCpuUsage**: obtains the historical CPUP of a task.<br>**LOS_AllTaskCpuUsage**: obtains the CPUP of all tasks.| 57| Outputting the task CPUP| **LOS_CpupUsageMonitor**: outputs the historical CPUP of a task.| 58| Obtaining the interrupt CPUP| **LOS_GetAllIrqCpuUsage**: obtains the CPUP of all interrupts.| 59 60## How to Develop 61 62In the **kernel/liteos_m** directory, run the **make menuconfig** command and choose **Kernel > Enable Cpup** to enable CPUP. 63 64Choose **Enable Cpup include irq** to enable interrupt CPUP. 65 66The typical CPUP development process is as follows: 67 681. Call **LOS_SysCpuUsage** to obtain the system CPUP. 69 702. Call **LOS_HistorySysCpuUsage** to obtain the historical CPUP of the system. 71 723. Call **LOS_TaskCpuUsage** to obtain the CPUP of a task. 73 - If the task has been created, disable interrupt, obtain the CPUP, and then enable interrupt. 74 - If the task is not created, return an error code. 75 764. Call **LOS_HistoryTaskCpuUsage** to obtain the historical CPUP of a task. 77 - If the task has been created, disable interrupt, obtain the CPUP in different modes, and then enable interrupt. 78 - If the task is not created, return an error code. 79 805. Call **LOS_AllCpuUsage** to obtain the CPUP of all tasks. 81 - If CPUP has been initialized, disable interrupt, obtain the CPUP in different modes, and then enable interrupt. 82 - If CPUP is not initialized or has invalid input parameters, return an error code. 83 84 85## Development Example 86 87 88### Example Description 89 90This example implements the following: 91 921. Create a task for the CPUP test. 93 942. Obtain the CPUP of the current system. 95 963. Obtain the historical system CPUP in different modes. 97 984. Obtain the CPUP of the created task. 99 1005. Obtain the CPUP of the created task in different modes. 101 102 103### Sample Code 104 105**Prerequisites** 106 107CPUP is enabled.<br>To enable CPUP, run **make menuconfig** in the **kernel/liteos_m** directory and choose **Kernel->Enable Cpup** to enable CPUP. 108 109The sample code is as follows: 110 111The sample code can be compiled and verified in **./kernel/liteos_m/testsuites/src/osTest.c**. The **ExampleCpup** function is called in **TestTaskEntry**. 112 113 114``` 115#include "los_task.h" 116#include "los_cpup.h" 117 118#define TEST_TASK_PRIO 5 119#define TASK_DELAY_TIME 100 120VOID CpupTask(VOID) 121{ 122 printf("entry cpup test example\n"); 123 usleep(TASK_DELAY_TIME); 124 usleep(TASK_DELAY_TIME); 125 printf("exit cpup test example\n"); 126} 127 128UINT32 ExampleCpup(VOID) 129{ 130 UINT32 ret; 131 UINT32 cpupUse; 132 UINT32 taskID; 133 TSK_INIT_PARAM_S cpupTestTask = { 0 }; 134 135 cpupTestTask.pfnTaskEntry = (TSK_ENTRY_FUNC)CpupTask; 136 cpupTestTask.pcName = "TestCpupTsk"; 137 cpupTestTask.uwStackSize = LOSCFG_BASE_CORE_TSK_DEFAULT_STACK_SIZE; 138 cpupTestTask.usTaskPrio = TEST_TASK_PRIO; 139 ret = LOS_TaskCreate(&taskID, &cpupTestTask); 140 if(ret != LOS_OK) { 141 printf("cpupTestTask create failed .\n"); 142 return LOS_NOK; 143 } 144 145 usleep(TASK_DELAY_TIME); 146 147 /* Obtain the current system CPUP. */ 148 cpupUse = LOS_SysCpuUsage(); 149 printf("the current system cpu usage is: %u.%u\n", 150 cpupUse / LOS_CPUP_PRECISION_MULT, cpupUse % LOS_CPUP_PRECISION_MULT); 151 152 /* Obtain the historical CPUP of the system. */ 153 cpupUse = LOS_HistorySysCpuUsage(CPUP_LESS_THAN_1S); 154 printf("the history system cpu usage in all time: %u.%u\n", 155 cpupUse / LOS_CPUP_PRECISION_MULT, cpupUse % LOS_CPUP_PRECISION_MULT); 156 157 /* Obtain the CPUP of a specified task. */ 158 cpupUse = LOS_TaskCpuUsage(taskID); 159 printf("cpu usage of the cpupTestTask:\n TaskID: %d\n usage: %u.%u\n", 160 taskID, cpupUse / LOS_CPUP_PRECISION_MULT, cpupUse % LOS_CPUP_PRECISION_MULT); 161 162 /* Obtain the CPUP of a specified task since the system starts. */ 163 cpupUse = LOS_HistoryTaskCpuUsage(taskID, CPUP_LESS_THAN_1S); 164 printf("cpu usage of the cpupTestTask in all time:\n TaskID: %d\n usage: %u.%u\n", 165 taskID, cpupUse / LOS_CPUP_PRECISION_MULT, cpupUse % LOS_CPUP_PRECISION_MULT); 166 167 return LOS_OK; 168} 169``` 170 171 172### Verification 173 174 The development is successful if the return result is as follows: 175 176``` 177entry cpup test example 178the current system cpu usage is: 8.2 179the history system cpu usage in all time: 8.9 180cpu usage of the cpupTestTask: 181 TaskID: 5 182 usage: 0.5 183cpu usage of the cpupTestTask in all time: 184 TaskID: 5 185 usage: 0.5 186 187exit cpup test example 188 189The preceding data may vary depending on the running environment. 190``` 191