B_ QuRT_ User_ Guide(38)

24 Performance Monitor

Threads use performance monitors to measure code performance in real time during user program execution .
Performance monitoring unit （PMU） yes Hexagon A hardware function of the processor . It is controlled by accessing a set of dedicated processor registers .
The performance monitor is QuRT The following operations are used to control .- qurt_pmu_enable()

• qurt_pmu_get()
• qurt_pmu_set()
• Macros

24.1 qurt_pmu_enable()

24.1.1 Function document

24.1.1.1 void qurt_pmu_enable ( int enable )

Enable or disable Hexagon Processor performance monitoring unit （PMU）. By default , Profiling is disabled .
Disabled by default .
Be careful ： Enabling profiling does not automatically reset the count register – Must be done explicitly before starting the event count .

Parameters

Return value
None.

Dependencies
None.

24.2 qurt_pmu_get()

24.2.1 Function document

24.2.1.1 unsigned int qurt_pmu_get ( int reg_id )

obtain PMU register .
Returns the specified PMU The current value of the register .

Parameters

Return value
Integer - Appoint PMU The current value of the register .
Dependencies
None.

24.3 qurt_pmu_set()

24.3.1 Function document

24.3.1.1 void qurt_pmu_set ( int reg_id, unsigned int reg_value )

Set specified PMU Register value .
Be careful ： Set up PMUEVTCFG It will automatically clear PMU register PMUCNT0 To PMUCNT3.
Parameters

Return value
None.

Dependencies
None.

25 Error Results

QuRT The function returns an error result in one of two ways .

• As the result value of the function
• As the value passed to the user-defined exception handler
  QuRT A set of standard symbols is defined for the error result value . This section lists these symbols and their corresponding values .

26 Function Tracing

QuRT Support function tracing to assist debugging programs .- qurt_trace_changed()

• qurt_trace_get_marker()
• qurt_etm_set_pc_range()
• qurt_etm_set_atb()
• qurt_stm_trace_set_config() - data type
• Macro instructions

26.1 qurt_trace_changed()

26.1.1 Function document

26.1.1.1 int qurt_trace_changed ( unsigned int prev_trace_marker, unsigned int trace_mask )

Determine whether a specific kernel event has occurred .
Returns a value , Indicates that since the specified kernel trace flag was obtained , Whether the specified kernel event is recorded in the kernel trace buffer .
prev_trace_marker Parameters are specified by calling qurt_trace_get_marker() Obtained kernel trace flags .
Be careful .
And qurt_trace_get_marker() Use it together , This function determines whether some kernel events occur in a code block .
This function cannot determine whether a specific kernel event type has occurred , Unless the event type is in trace_mask Element is enabled .
QuRT Only interrupt and context switching events are supported （ Such as trace_mask The value is 0x3）.
Parameters

Return value
1 - Since obtaining the specified trace mark , The specified type of kernel event has occurred .
0 - Since obtaining the specified trace mark , No kernel event of the specified type occurred .

Dependencies
None.

26.2 qurt_trace_get_marker()

26.2.1 Function document

26.2.1.1 unsigned int qurt_trace_get_marker ( void )

Get kernel trace flags .
Returns the current value of the kernel trace tag . The tag consists of a hardware thread identifier and an index of the kernel trace buffer . The trace buffer records various kernel events .
Be careful ： Let's combine this function with qurt_trace_changed() Together, you can determine whether some kernel events occur in a code block .
Return value
Integer - Kernel trace flags .
Dependencies
None.

26.3 qurt_etm_set_pc_range()

26.3.1 Function document

26.3.1.1 unsigned int qurt_etm_set_pc_range ( unsigned int range_num, unsigned int low_addr, unsigned int high_addr )

Setting is used for ETM The filter PC Address range . according to Hexagon Core design , It can support up to four PC Range .
Parameters

Return value
QURT_ETM_SETUP_OK - success .
QURT_ETM_SETUP_ERR - Failure .
Dependencies
None.

26.4 qurt_etm_set_atb()

26.4.1 Function document

26.4.1.1 unsigned int qurt_etm_set_atb ( unsigned int flag )

Set up ATB Status of the bus , To inform QuRT ATB The bus is actively enabled or disabled .QuRT perform
Perform corresponding actions under low power management .
Parameters

Return value
QURT_ETM_SETUP_OK - success .
QURT_ETM_SETUP_ERR - Failure
Dependencies
None.

26.5 qurt_stm_trace_set_config()

26.5.1 Function document

26.5.1.1 unsigned int qurt_stm_trace_set_config ( qurt_stm_trace_info_t ∗ stm_config_info )

Set up a STM Ports are used to track events .
Parameters

Return value
QURT_EOK - success .
QURT_EINVALID - Failure ; It may be because the port address passed is not in the page table .

Dependencies
None.

26.6 Data Types

This section introduces the data types of function tracking service .

26.6.1 Data Structure Documentation

26.6.1.1 struct qurt_stm_trace_info_t

26.7 Macros

STM Tracking information .

26.7.1 Define Documentation 26.7.1.1 #define QURT_ETM_SETUP_OK 0

ETM setup OK.

26.7.1.2 #define QURT_ETM_SETUP_ERR 1

ETM setup error.

26.7.1.3

ATB off.

26.7.1.4

ATB on.

26.7.1.5 #define QURT_TRACE( str, … ) VA_ARGS

Function tracing is through a debug macro （QURT_TRACE） Realized , It can choose to generate printf
sentence , Before and after every function call passed as a macro parameter . for example , The following macro calls in the source code ：

 QURT_TRACE(myfunc, my_func(33))

The following debug output is generated ：

       myfile:nnn: my_func >>> calling my_func(33)
       myfile:nnn: my_func >>> returned my_func(33)

The debug output includes the source file and line number of the function call , And the text of the call itself . When compiling the client source file , Its file name is defined -D FILENAME.
Debug output is to use functions in the Library qurt_printf Generated . Symbol QURT_DEBUG Control the generation of debug output . If this symbol is not defined , Function trace will not be generated .
Be careful ： Debug macro is passed QuRT API Header file access .