measurecst_hrtimer_printf.c

embOS的MSP430F2274移植版

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*       Solutions for real time microcontroller applications         *
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*       embOS version: 3.60a                                         *
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----------------------------------------------------------------------
File    : MeasureCST_HRTimer_Printf.c
Purpose : Performance test program for OS
          This benchmark measures the context switching time and displays 
          the result on CSpy's terminal I/O window. It runs with every
          IAR workbench that supports terminal I/O with printf.
--------  END-OF-HEADER  ---------------------------------------------
*/

#include "RTOS.h"
#include "stdio.h"

static OS_STACKPTR int StackHP[128], StackLP[128];  // Task stacks
static OS_TASK TCBHP, TCBLP;                        // Task-control-blocks
static OS_U32 _Time;                                // Timer value for context switching measurement

/*********************************************************************
*
*       HPTask
*/
static void HPTask(void) {
  while (1) {
    OS_Suspend(NULL);              // Suspend high priority task 
    OS_Timing_End(&_Time);         // Stop measurement
  }  
}

/*********************************************************************
*
*       LPTask
*/
static void LPTask(void) {
  OS_U32 MeasureOverhead;          // Time for Measure Overhead
  OS_U32 v;                        // Real context switching time
  
  //
  // Measure overhead for time measurement so we can take this into account by subtracting it
  //
  OS_Timing_Start(&MeasureOverhead);
  OS_Timing_End(&MeasureOverhead);
  //
  // Perform measurements in endless loop
  //
  while (1) {
    OS_Delay(100);                 // Syncronize to tick to avoid jitter
    OS_Timing_Start(&_Time);       // Start measurement
    OS_Resume(&TCBHP);             // Resume high priority task to force task switch
    v = OS_Timing_GetCycles(&_Time) - OS_Timing_GetCycles(&MeasureOverhead); // Calculate real context switching time (w/o measurement overhead)
    v = OS_ConvertCycles2us(1000 * v);                                       // Convert cycles to nano-seconds, increase time resolution
    printf("Context switch time: %u.%.3u usec\r\n", v / 1000, v % 1000);     // Print out result
  }
}

/*********************************************************************
*
*       main
*/
int main(void) {
  OS_IncDI();                      // Initially disable interrupts  
  OS_InitKern();                   // Initialize OS                 
  OS_InitHW();                     // Initialize Hardware for OS    
  OS_CREATETASK(&TCBHP, "HP Task", HPTask, 100, StackHP);
  OS_CREATETASK(&TCBLP, "LP Task", LPTask,  99, StackLP);
  OS_Start();                      // Start multitasking            
  return 0;
}