Execution time measurement

This stack overflow article seems to describe the problem.
http://stackoverflow.com/questions/15030123/how-does-the-clock-function-in-ctime-access-the-system-clock

It might just be easier to use one of the PS timers; Adam Taylor has a nice intro:
http://forums.xilinx.com/t5/Xcell-Daily-Blog/Implementing-the-Zynq-SoC-s-Private-Timer-Adam-Taylor-s-MicroZed/ba-p/402203

This gave me an excuse to play with the timer stuff, the attached is a working 100 microsecond timer with a stub function that seems to satisfy _that one particular_ missing library function (ie: ymmv); two files 'substitute_times.h' and 'substitute_times.cpp'

**/// snip ///**

/*
* substitute_times.h
*
*  simple interrupt driven timer to stand-in for standard lib
*  function 'times'
*/

#ifndef SUBSTITUTE_TIMES_H_
#define SUBSTITUTE_TIMES_H_

#include <xscugic.h>

///@note the arm-xilinx-eabi library function '_times' itself already declared; we won't do it again

/** Installs a timer interrupt handler and initialize the system timer to generate a timer interrupt every 100 microseconds.
* The interrupt routine maintains a software divider to generate CLOCKS_PER_SEC frequency.
* and install a handler to process the interrupt and increment a counter.
* @note call from your interrupt configuration routine, before you globally enable interrupts.
* @note enables timer interrupt and also GIC interrupt for timer.
* @param pInterruptControllertreference to interrupt controller
*/
void init_substitute_times(XScuGic *pInterruptController);

/** stop the interrupts, kill the timer */
void kill_substitute_times();

/** elapsed microseconds since boot */
uint64_t getMicroseconds();

/** elapsed CLOCKS_PER_SEC since boot */
clock_t getClocks();

#endif /* SUBSTITUTE_TIMES_H_ */

**/// snip ///**

/*
* substitute_times.cpp
*/

#include <stdint.h>
#include <ctime>
#include <sys/times.h>

#include <xil_types.h>
#include <xparameters.h>
#include <xscutimer.h>
#include <xscugic.h>

/**tTimer interrupt period in microseconds.
*
* from "xparameters.h" we know that
* XPAR_PS7_CORTEXA9_0_CPU_CLK_FREQ_HZ is system clock (~667MHz on my microZed)
*
* from the Zynq-700 SoC reference we know that:
* tt8.2.1 Clocking
*ttAll private timers and watchdog timers are always clocked at 1/2 of the CPU frequency (CPU_3x2x).
*
* from "time.h" we know CLOCKS_PER_SEC = 100.
*
* so for example we can use 3333333 as a divisor for 100.00001305 Hz
*
* From <http://forums.xilinx.com/t5/Xcell-Daily-Blog/Implementing-the-Zynq-SoC-s-Private-Timer-Adam-Taylor-s-MicroZed/ba-p/402203>
* twe steal code liberally...
*
*/
const uint32_t timer_period_microseconds = 100;

const uint32_t timer_freq = 1000000/timer_period_microseconds;

/**tTimer divisor to give us 'timer_period_microseconds' intervals
*/
const uint32_t divisor_for_timer = (XPAR_PS7_CORTEXA9_0_CPU_CLK_FREQ_HZ/2) / timer_freq;

const uint32_t timer_periods_per_CLOCK = timer_freq/CLOCKS_PER_SEC;


/// incremented at CLOCKS_PER_SEC by timer interrupt
volatile clock_t clock_value = 0;


/// will contain ref to ARM 'private' timer
static XScuTimer substitute_tick_timer;

/// incremented every 'timer_period_microseconds' by timer interrupt; not necessarily incremented by 1 !!
volatile uint64_t microsecond_counter = 0;

// incremented each timer interrupt, when it equals timer_periods_per_CLOCK then 'clock_value' is incremented
volatile uint64_t CLOCK_counter = 0;

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

extern "C"
{
t/** substitute for missing arm-xilinx-eabi library '_times' symbol.
t * @note the '_times' function itself already declared; we won't do it again
t */
tclock_t _times(tms * ptms)
t{
ttif (ptms)
tt{
ttt// fill in struct in vaguely appropriate fashion
tttptms->tms_utime = 0;  /* user time */
tttptms->tms_stime = clock_value;  /* system time */
tttptms->tms_cutime = 0; /* user time of children */
tttptms->tms_cstime = 0; /* system time of children */
tt}
ttreturn clock_value;
t}
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

uint64_t getMicroseconds() { return microsecond_counter; }
clock_t getClocks() { return clock_value; }

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

/** timer interrupt handler
* @param CallBackRefta reference to our XScuTimer
*/
static void handler_substitue_times(void *CallBackRef)
{
tXScuTimer *pTimer = (XScuTimer *) CallBackRef;t// ideally, equal to 'substitute_tick_timer'

tmicrosecond_counter += timer_period_microseconds;

tCLOCK_counter += 1;
tif (CLOCK_counter == timer_periods_per_CLOCK)
t{
ttclock_value += 1;
ttCLOCK_counter = 0;
t}

tXScuTimer_ClearInterruptStatus(pTimer);
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void init_substitute_times(XScuGic *pInterruptController)
{
    //timer initialization

tXScuTimer_Config* pTimerConfig = XScuTimer_LookupConfig(XPAR_XSCUTIMER_0_DEVICE_ID);

tif (pTimerConfig)
t{
ttXScuTimer_CfgInitialize(&substitute_tick_timer, pTimerConfig, pTimerConfig->BaseAddr);

ttXScuTimer_SelfTest(&substitute_tick_timer); // hmmm

tt//load the timer

ttXScuTimer_LoadTimer(&substitute_tick_timer, divisor_for_timer);
t tXScuTimer_EnableAutoReload(&substitute_tick_timer);

t t//set up the interrupts
ttXScuGic_Connect(pInterruptController, XPAR_SCUTIMER_INTR, (Xil_ExceptionHandler)handler_substitue_times, (void *)&substitute_tick_timer);

tt//enable the interrupt for the Timer at GIC
ttXScuGic_Enable(pInterruptController, XPAR_SCUTIMER_INTR);
tt//enable interrupt on the timer
ttXScuTimer_EnableInterrupt(&substitute_tick_timer);

t t//start timer
t tXScuTimer_Start(&substitute_tick_timer);
t}
telse
t{
tt// whoops, no timer? bad ID?
t}
}

void kill_substitute_times()
{
t//disable interrupt on the timer
tXScuTimer_DisableInterrupt(&substitute_tick_timer);
tXScuTimer_Stop(&substitute_tick_timer);
}

Thanks so much for the reply.
I want to try your header file, but the funny thing is that when I include xscugic.h header, it say "no such file or directory". And also the xscutimer.h and xil_types.h . But the fact is that I can find these files in the Myproject_bsp folder.
Do you know the reason?

Thanks so much for the reply.
I want to try your header file, but the funny thing is that when I include xscugic.h header, it say "no such file or directory". And also the xscutimer.h and xil_types.h . But the fact is that I can find these files in the Myproject_bsp folder.
Do you know the reason?