https://github.com/GorgonMeducer/perf_counter
A dedicated performance counter mainly for micro-controllers. For Cortex-M processors, the Systick will be used by default. The `perf_counter` shares the SysTick with users' original SysTick function(s) without interfering with it. This library will bring new functionalities.
https://github.com/GorgonMeducer/perf_counter
cortex-m delay microcontroller performance-analysis performance-counters systick
Last synced: about 21 hours ago
JSON representation
A dedicated performance counter mainly for micro-controllers. For Cortex-M processors, the Systick will be used by default. The `perf_counter` shares the SysTick with users' original SysTick function(s) without interfering with it. This library will bring new functionalities.
- Host: GitHub
- URL: https://github.com/GorgonMeducer/perf_counter
- Owner: GorgonMeducer
- License: apache-2.0
- Created: 2021-01-09T13:03:54.000Z (about 5 years ago)
- Default Branch: CMSIS-Pack
- Last Pushed: 2026-01-26T16:21:18.000Z (about 1 month ago)
- Last Synced: 2026-01-27T04:45:28.629Z (about 1 month ago)
- Topics: cortex-m, delay, microcontroller, performance-analysis, performance-counters, systick
- Language: C
- Homepage:
- Size: 13 MB
- Stars: 556
- Watchers: 16
- Forks: 101
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-mcu-embedded - perf_counter - M systick. It shares the SysTick with users' original SysTick function without interfering it. This library will bring new functionalities, such as performance counter, delay_us and clock() service defined in time.h (component / timer)
README
[](https://deepwiki.com/GorgonMeducer/perf_counter)  
# perf_counter (v2.5.4)
A dedicated performance counter mainly for micro-controllers.
For Cortex-M processors, the Systick will be used by default. The `perf_counter` shares the SysTick with users' original SysTick function(s) without interfering with it. This library will bring new functionalities, such as performance counter,` perfc_delay_us`, `perfc_delay_ms` and `clock()` service defined in `time.h`.
A dedicated template is provided to port the perf_counter to different architectures or using a different Timer instead of SysTick in Cortex-M processors.
### Features:
- **Measure CPU cycles for specified code segment**
- **Add Coremark 1.0**
- **Provide Timer Service for EventRecorder automatically.**
- **Enhanced measurement services for RTOS**
- Measures **RAW / True** cycles used for specified code segment inside a thread, **i.e. scheduling cost are removed**.
- Measure **RAW/True** cycles used for a data-process-path across multiple threads.
- **Easy to use**
- Helper macros: `__cycleof__()` , `__super_loop_monitor__()` , `__cpu_usage__()`, `__cpu_perf__() `etc.
- Helper functions: `start_cycle_counter()`, `stop_cycle_counter()` etc.
- Enable a broader processor architecture support
- **Support ALL Cortex-M processors**
- SysTick
- Performance Monitor Unit (PMU)
- Easy to port to a different architecture with a porting template
- **Provide Free Services**
- Would **NOT** interfere with existing SysTick-based applications
- **Support most of the arm compilers**
- Arm Compiler 5 (armcc), Arm Compiler 6 (armclang)
- arm gcc
- LLVM
- IAR
- **Simplified Deployment**
- **Drag-and-Drop deployment for Arm Compiler 5 and Arm Compiler 6.**
- **CMSIS-Pack is available**
- **RT-Thread package is avaialble**
- **Time-based services**
- `perfc_delay_us()` and `perfc_delay_ms()` with **64bit return value**.
- Adds weak entries `perfc_delay_us_user_code_in_loop()` and `perfc_delay_ms_user_code_in_loop()` for users to override, e.g. feeding the watchdog.
- Provides Timestamp services via `get_system_ticks()`, `get_system_us` and `get_system_ms()`.
- When passing `false` to `perfc_init()`, it is possible to use perf_counter in ISRs or global interrupt handling is disabled.
- Users can call micro-seconds related APIs even when the system timer clock is less than 1MHz.
- **Support both RTOS and bare-metal environments**
- Supports SysTick Reconfiguration
- Supports changing System Frequency
- Supports stack-overflow detection in RTOS environment via `perfc_check_task_stack_canary_safe()`
- Adds macro `__PERFC_SAFE ` to avoid blocking high priority ISRs and tasks. Users should define the system timer priority level with macro `__PERFC_SYSTIMER_PRIORITY__ `. In Cortex-M, `0` means the highest configurable exception level.
- **Utilities for C language enhancement**
- Macros to detect compilers, e.g. `__IS_COMPILER_ARM_COMPILER_6__`, `__IS_COMPILER_LLVM__` etc.
- Macros to detect compiler features:
- `__COMPILER_HAS_GNU_EXTENSIONS__`
- `__IS_COMPILER_SUPPORT_C99__`
- `__IS_COMPILER_SUPPORT_C11__`
- Macro to create atomicity for a specified code block, i.e. `__IRQ_SAFE{...}`.
- Helper macros for C language extension:
- VB like `with()`
- `foreach()`, `dimof()` and `CONNECT()`
- C# like `using()`
- simple overload feature of OOPC made out of ANSI-C99, `__PLOOC_VA_NUM_ARGS()`.
- ...
- A dedicated macro `__perfc_sync_barrier__()` for code barrier.
- Macros to measure stack usage
- Adds a macro `__stack_usage__()` and `__stack_usage_max__()` to measure the stack usage for a given code segment.
- Adds a macro `ISR()` to measure the stack usage of a given Cortex-M Exception handling.
- You can define macro `__PERFC_STACK_CHECK_IN_ISR__` in project configuration to enable this feature.
- You can define macro `__PERFC_STACK_WATERMARK_U32__` in your project configuration to override the default watermark, i.e. `0xDEADBEEF`.
- Supports for architectures that use growing-upward stacks. You can define macro `__PERFC_STACK_GROWS_UPWARD__` to switch.
- Adds C Language Extensions
- Adds Coroutine support
- Adds watermark to stack and users can call `perfc_coroutine_stack_remain()` to get the stack usage info.
- Defining macro `__PERFC_COROUTINE_NO_STACK_CHECK__` in **compilation command line** disables the stack-checking feature.
- Adds protoThread support with/without the coroutine.
- Adds timeout feature in **wait_xxxx**
### Important Updates
- Following functions/macros are **deprecated**, please use the version with `perfc_` as prefix:
- `init_cycle_counter()` -> `perfc_init()`
- `delay_us()` -> `perfc_delay_us()`
- `delay_ms()` -> `perfc_delay_ms()`
- `CONNECT()` -> `PERFC_CONNECT()`
- `using()` -> `perfc_using()`
- `with()` -> `perfc_with()`
- `foreach()` -> `perfc_foreach()`
- You can define the macro `__PERFC_NO_DEPRECATED__` to disable the alias of the deprecated APIs.
## 1. How To Use
### 1.1 Measure CPU cycles for a specified code segment
You can measure a specified code segment with a macro helper `__cycleof__()`, a wrapper of `get_system_ticks()`.
**Syntax:**
```c
__cycleof__(, [User Code, see ref 1]) {
//! target code segment of measurement
...
}
```
Here, [**ref 1**] is a small user code to read the measurement result via a local variable `__cycle_count__`. This User Code is optional. If you don't put anything here, the measured result will be shown with a `__perf_counter_printf__`.
> [!NOTE]
>
> The first parameter cannot be ignored. If you don't want to give a description string, please pass an empty string i.e. "".
#### **Example 1:** Simple measurement with `printf()`
```c
__cycleof__("") {
foreach(example_lv0_t, s_tItem, ptItem) {
__perf_counter_printf__("Processing item with ID = %d\r\n", _->chID);
}
}
```
You will see the measured result in the console:
#### **Example 2:** Read measured result via `__cycle_counter__`
```c
int64_t lCycleResult = 0;
/* measure cycles and store it in a dedicated variable without printf */
__cycleof__("delay_us(1000ul)",
/* insert code to __cycleof__ body, "{}" can be omitted */
{
lCycleResult = __cycle_count__; /*< "__cycle_count__" stores the result */
}) {
perfc_delay_us(1000ul);
}
__perf_counter_printf__("\r\n delay_us(1000ul) takes %lld cycles\r\n", lCycleResult);
```
The result is read out from `__cycle_count__`and used in other place:
### 1.2 Performance Analysis
#### 1.2.1 CPU Usage
For both bare-metal and OS environments, you can measure the CPU Usage with macro `__cpu_usage__()` for a given code segment as long as it is executed repeatedly.
**Syntax**
```c
__cpu_usage__(, [User Code, see ref 1]) {
//! target code segment of measurement
...
}
```
Here, [**ref 1**] is a small user code to read the measurement result via a local variable `__usage__`. This User Code is optional. If you don't put anything here, the measured result will be shown with a `__perf_counter_printf__`.
##### **Example 1: the following code will show 30% of CPU Usage:**
```c
void main(void)
{
...
while (1) {
__cpu_usage__(10) {
perfc_delay_us(30000);
}
perfc_delay_us(70000);
}
...
}
```
##### Example 2: Read measurement result via `__usage__`
```c
void main(void)
{
...
while (1) {
__cpu_usage__(10, {
float fUsage = __usage__; /*< "__usage__" stores the result */
__perf_counter_printf__("task 1 cpu usage %3.2f %%\r\n", (double)fUsage);
}) {
perfc_delay_us(30000);
}
perfc_delay_us(70000);
}
...
}
```
> [!NOTE]
>
> The `__usage__` stores the percentage information.
#### 1.2.2 Cycle per Instruction and L1 DCache Miss Rate
For **Armv8.1-m** processors that implement the **PMU**, it is easy to measure the **CPI** (Cycle per Instruction) and **L1 DCache miss rate** with the macro `__cpu_perf__()`.
**Syntax**:
```c
__cpu_perf__(, [User Code, see ref 1]) {
//! target code segment of measurement
...
}
```
Here, [**ref 1**] is a small user code to read the measurement result via a local **struct** variable `__PERF_INFO__`. This User Code is optional. If you don't put anything here, the measured result will be shown with a `__perf_counter_printf__`. The prototype of the `__PERF_INFO__` is shown below:
```c
struct {
uint64_t dwNoInstr; /* number of instruction executed */
uint64_t dwNoMemAccess; /* number of memory access */
uint64_t dwNoL1DCacheRefill; /* number of L1 DCache Refill */
int64_t lCycles; /* number of CPU cycles */
uint32_t wInstrCalib;
uint32_t wMemAccessCalib;
float fCPI; /* Cycle per Instruction */
float fDCacheMissRate; /* L1 DCache miss rate in percentage */
} __PERF_INFO__;
```
For example, when inserting user code, you can read CPI from `__PERF_INFO__.fCPI`.
**Example 1: measure the Coremark**
```c
void main(void)
{
perfc_init(false);
__perf_counter_printf__("Run coremark\r\n");
#ifdef __PERF_COUNTER_COREMARK__
__cpu_perf__("Coremark") {
coremark_main();
}
#endif
while(1) {
__NOP();
}
}
```
The result might look like the following:
### 1.3 Timestamp
You can get the system timestamp (since the initialization of perf_counter service) via the functions `get_system_ticks()` and `get_system_ms()`.
> [!NOTE]
>
> The `get_system_ms()` is **NOT** a wrapper of the function `get_system_ticks()`.
There are various ways to take advantage of those functions.
#### Example 3: Use `get_system_ms()` as random seed
```c
#include
#include
#include "perf_counter.h"
int main (void)
{
int i, n;
...
n = 5;
/* Initialize random number generator */
srand((unsigned) get_system_ticks());
/* Print 5 random numbers from 0 to 1024 */
for( i = 0 ; i < n ; i++ ) {
__perf_counter_printf__("%d\n", rand() & 0x3FF);
}
return(0);
}
```
#### Example 4: Measure CPU cycles
```c
do {
int64_t tStart = get_system_ticks();
__IRQ_SAFE {
__perf_counter_printf__("no interrupt \r\n");
}
__perf_counter_printf__("used clock cycle: %d", (int32_t)(get_system_ticks() - tStart));
} while(0);
```
This example shows how to use the delta value of `get_system_ticks()` to measure the CPU cycles used by a specified code segment. In fact, the `__cycleof__()` is implemented in the same way:
```c
#define __cycleof__(__STR, ...) \
perfc_using(int64_t _ = get_system_ticks(), __cycle_count__ = _, \
{__perfc_sync_barrier__();}, \
{ \
__perfc_sync_barrier__(); \
_ = get_system_ticks() - _ - g_nOffset; \
__cycle_count__ = _; \
if (__PLOOC_VA_NUM_ARGS(__VA_ARGS__) == 0) { \
__perf_counter_printf__("\r\n"); \
__perf_counter_printf__("-[Cycle Report]"); \
__perf_counter_printf__( \
"------------------------------------\r\n"); \
__perf_counter_printf__( \
__STR " total cycle count: %ld [%08lx]\r\n", \
(long)_, (long)_); \
} else { \
__VA_ARGS__ \
}; \
})
```
### 1.4 Timer Services
perf_counter provides the basic timer services for delaying a given period and polling-for-timeout. For example:
```c
perfc_delay_ms(1000); /* block the program for 1000ms */
perfc_delay_us(50); /* block the program for 50us */
while(1) {
/* return true every 1000 ms */
if (perfc_is_time_out_ms(1000)) {
/* print hello world every 1000 ms */
__perf_counter_printf__("\r\nHello world\r\n");
}
}
```
### 1.5 Work with EventRecorder in MDK
If you are using EventRecorder in MDK, once you deploy the `perf_counter`, it will provide the timer service for EventRecorder by implementing the following functions: `EventRecorderTimerSetup()`, `EventRecorderTimerGetFreq()` and `EventRecorderTimerGetCount()`.
If you have not modified anything in `EventRecorderConf.h`, **you don't have to**, and please keep the default configuration. If you see warnings like this:
```
Invalid Time Stamp Source selected in EventRecorderConf.h!
```
Please set the macro `EVENT_TIMESTAMP_SOURCE` to `3` to suppress it.
> [!IMPORTANT]
>
> Please always make sure the macro `EVENT_TIMESTAMP_FREQ` is `0`
**By using perf_counter as the reference clock, EventRecorder can have the highest clock resolution on the target system without worrying about the presence of DWT or any conflicting usage of SysTick.**
### 1.6 On System Environment Changing
#### 1.6.1 System Frequency Changing
If you want to change the System Frequency, **after** the change, make sure:
1. The `SystemCoreClock` has been updated with the new system frequency. Usually, the HAL will update the `SystemCoreClock` automatically, but in some rare cases where `SystemCoreClock` is updated accordingly, you should do it yourself.
2. please call `update_perf_counter()` to notify perf_counter.
#### 1.6.2 Reconfigure the SysTick
Some systems (e.g., FreeRTOS) might reconfigure the systick timer to fulfill the requirements of their feature. To support this:
1. **Before the reconfiguration**, please call function `before_cycle_counter_reconfiguration()`.
**NOTE**: This function will stop the SysTick, clear the pending bit, and set the Load register and the Current Value registers to zero.
2. After the reconfiguration, please call `update_perf_counter()` to notify perf_counter the new changes.
## 2. How To Deploy
### 2.1 Generic(Default) method for all compilers
#### 2.1.1 For Bare-metal:
1. Clone the code to your local with the following command lines:
```shell
git clone https://github.com/GorgonMeducer/perf_counter.git
```
2. Add including path for `perf_counter` folder
3. Add `perf_counter.c` and `perfc_port_default.c` to your project for compilation.
> [!IMPORTANT]
>
> Please do **NOT** add any assembly source files of this `perf_counter` library to your compilation, i.e. `systick_wrapper_gcc.S`, `systick_wrapper_gnu.s` or `systick_wrapper_ual.s`.
4. Include `perf_counter.h` in the corresponding c source file:
```c
#include "perf_counter.h"
```
5. Make sure your system contains the CMSIS (with version 5.7.0 or above) as `perf_counter.h` and includes `cmsis_compiler.h`.
6. Call the function `perfc_port_insert_to_system_timer_insert_ovf_handler()` in your `SysTick_Handler()`
```c
void SysTick_Handler(void)
{
...
perfc_port_insert_to_system_timer_insert_ovf_handler();
...
}
```
7. Ensure the `SystemCoreClock` is updated with the same value as CPU frequency.
> [!IMPORTANT]
>
> Make sure the `SysTick_CTRL_CLKSOURCE_Msk` bit ( bit 2) of `SysTick->CTRL` register is `1` that means SysTick runs with the same clock source as the target Cortex-M processor.
8. Initialize the perf_counter with a boolean value that indicates whether the user applications and/or RTOS have already occupied the SysTick.
```c
void main(void)
{
//! setup system clock
/*! \brief Update SystemCoreClock with the latest CPU frequency
*! If the function doesn't exist or doesn't work correctly,
*! Please update SystemCoreClock directly with the correct
*! system frequency in Hz.
*!
*! extern volatile uint32_t SystemCoreClock;
*/
SystemCoreClockUpdate();
/*! \brief initialize perf_counter() and pass true if SysTick is
*! occupied by user applications or RTOS; otherwise, pass
*! false.
*/
perfc_init(true);
...
while(1) {
...
}
}
```
> [!IMPORTANT]
>
> Please enable the GNU extension in your compiler. For **GCC** and **CLANG**, it is `--std=gnu99` or `--std=gnu11`, and for other compilers, please check the user manual first. Fail to do so, you will not only trigger the warning in `perf_counter.h`, but also lose the function correctness of `__cycleof__()` and `__super_loop_monitor__()`, because `__PLOOC_VA_NUM_ARGS()` doesn't report `0` when passed with no argument.
```c
#if !__COMPILER_HAS_GNU_EXTENSIONS__
#warning Please enable GNC extensions that is required by __cycleof__() and \
__super_loop_monitor__()
#endif
```
9. It is nice to add macro definition `__PERF_COUNTER__` to your project GLOBALLY. It helps other modules to detect the existence of perf_counter. For Example, LVGL [`lv_conf_cmsis.h`](https://github.com/lvgl/lvgl/blob/d367bb7cf17dc34863f4439bba9b66a820088951/env_support/cmsis-pack/lv_conf_cmsis.h#L81-L99) use this macro to detect perf_counter and uses `get_system_ms()` to implement `lv_tick_get()`.
10. It is nice to add `-include "perfc_common.h"` (or using equivalent option of your compiler) to the command line **GLOBALLY**.
**Enjoy !**
### 2.2 Use cmsis-pack in MDK
1. Download the cmsis-pack from the`cmsis-pack` folder. It is a file with name `GorgonMeducer.perf_counter..pack`, for example `GorgonMeducer.perf_counter.2.2.0.pack`
2. Double-click it to install this cmsis-pack. Once finished, you can find it in your Pack-Installer:
In the future, you can pull the latest version of perf_counter from the menu `Packs->Check For Updates` as shown below:
3. Open the RTE management window, find the **Utilities** and select the **Core**::**Source** inside perf_counter as shown below:
4. Include `perf_counter.h` in the corresponding c source file:
```c
#include "perf_counter.h"
```
5. Make sure your system contains the CMSIS (version 5.7.0 or above) as `perf_counter.h` and includes `cmsis_compiler.h`. Usually, you should do this with RTE, as shown below:
6. Ensure the `SystemCoreClock` is updated with the same value as CPU frequency.
> [!IMPORTANT]
>
> Make sure the `SysTick_CTRL_CLKSOURCE_Msk` bit ( bit 2) of `SysTick->CTRL` register is `1` that means SysTick runs with the same clock source as the target Cortex-M processor.
7. Initialize the perf_counter with a boolean value that indicates whether the user applications and/or RTOS have already occupied the SysTick.
```c
void main(void)
{
//! Setup system clock
/*! \brief Update SystemCoreClock with the latest CPU frequency
*! If the function doesn't exist or doesn't work correctly,
*! Please update SystemCoreClock directly with the correct
*! system frequency in Hz.
*!
*! extern volatile uint32_t SystemCoreClock;
*/
SystemCoreClockUpdate();
/*! \brief initialize perf_counter() and pass true if SysTick is
*! occupied by user applications or RTOS; otherwise, pass
*! false.
*/
perfc_init(true);
...
while(1) {
...
}
}
```
8. Please enable the **GNU extension** in your compiler.
For Arm Compiler 5, please select both **C99 mode** and GNU extensions in the **Option for target dialogue** as shown below:
For Arm Compiler 6, please select **gnu99** or **gnu11** in Language C drop-list as shown below:
Failed to do so, you will not only trigger the warning in `perf_counter.h`, but also lose the function correctness of `__cycleof__()` and `__super_loop_monitor__()`, because `__PLOOC_VA_NUM_ARGS()` doesn't report `0` when passed with no argument.
```c
#if !__COMPILER_HAS_GNU_EXTENSIONS__
#warning Please enable GNC extensions, that is required by __cycleof__() and \
__super_loop_monitor__()
#endif
```
### 2.3 Use perf_counter in RT-Thread RTOS
perf_counter has registered as one of the [RT-Thread software packages](https://packages.rt-thread.org/en/detail.html?package=perf_counter), which locats in `system` category. In [ENV](https://www.rt-thread.io/download.html?download=Env) or [RT-Thread Studio](https://www.rt-thread.io/download.html?download=Studio), you just need to enable `cputime` framework. RT-Thread will automatically enable perf_counter if you are using Cortex-M architecture.
**Enjoy !**
## 3. FAQ
### 3.1 Why I see `Undefined symbol $Super$$SysTick_Handler`
This error usually appears in **Arm Compiler 5** and **Arm Compiler 6**. It is because you haven't implemented any non-weak `SysTick_Handler()`. Please provide an EMPTY one in any c source file to solve this problem:
```c
void SysTick_Handler(void)
{
}
```
**NOTE**: If you deploy perf_counter using cmsis-pack and encounter this issue, please **DO NOT** call function `user_code_insert_to_systick_handler()` in this **should-be-empty** `SysTick_Handler()`.
### 3.2 Why do I see perf_counter in red in the MDK project manager?
Since version v2.1.0, I removed the unnecessary bundle feature from the cmsis-pack. If you have used the older version, you will encounter this issue. To solve this problem:
1. please unselect ALL the performance components in RTE, press OK and close the uVision.
2. reopen the mdk project and select the perf_counter components in RTE
Sorry about this inconvenience.
### 3.3 How to feed the watchdog in `perfc_delay_ms()`?
Since version v2.5.0, it is possible to feed the watchdog while waiting for `perfc_delay_ms()` to return. You can implement a function called `perfc_delay_ms_user_code_in_loop()` in ANY of your C source file and use it to feed the watchdog:
```c
bool perfc_delay_ms_user_code_in_loop(int64_t lRemainInMs)
{
UNUSED_PARAM(lRemainInMs); /* the lRemainInMs tells you about the remaining time in ms */
extern void feed_watchdog(void);
feed_watchdog();
/* return false to exit the perfc_delay_ms() earlier */
/* usually, we just return true to wait until the end of the target period */
return true;
}
```
### 3.4 Can I use perf_counter APIs in ISRs and/or when the global interrupt is disabled?
YES. For such scenario, please initialize the **perf_counter** with:
```c
perfc_init(false);
```
and make sure the system timer (e.g. **SysTick**) is only used by **perf_counter.** If the SysTick is used by an RTOS or other applications, you can port perf_counter to a different timer using the `perfc_port_user.h` and `perfc_port_user.c` stored in the `template` folder.
## 4. License
The **Performance Counter** for Microcontrollers, a.k.a. ***perf_counter*** is under Apache 2.0 license.