Exemples

Clock

clock.c

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sched.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

void measure (int mode, int samples)
{
    struct timespec start_time;
    struct timespec stop_time;
    clock_gettime (mode, &start_time);  // setup...
    clock_gettime (mode, &start_time);
    for (int i = 0; i<samples; i++)
    {
        clock_gettime (mode, &start_time);
        clock_gettime (mode, &stop_time);
        long long t = (stop_time.tv_nsec - start_time.tv_nsec) +
            (stop_time.tv_sec - start_time.tv_sec) * 1000000000;
        printf ("%lld\n", t);
    }

}


/**
 * main program...
 */
int main(int argc, char* argv[])
{
    cpu_set_t my_set;
    CPU_ZERO(&my_set);
    CPU_SET(2, &my_set);
    sched_setaffinity(0, sizeof(cpu_set_t), &my_set);

    printf ("clocks_per_sec=%ld\n", CLOCKS_PER_SEC);

    int samples = 1000;
    if (argc == 2)
        samples = atol(argv[1]);

    struct timespec start_time;
    clock_getres (CLOCK_MONOTONIC_RAW, &start_time);
    long t = start_time.tv_sec * 1000000000 + start_time.tv_nsec;
    printf ("time=%ld'%03ld'%03ld ns\n", t/1000000, (t/1000)%1000, t%1000);

    measure (CLOCK_MONOTONIC_RAW, samples);

    return 0;
}

Makefile

EXE=clock
SRCS=$(wildcard *.c)

ifeq ($(target),)
target=nano
endif

CFLAGS=-Wall -Wextra -g -c -O0 -MD -std=gnu11 -D_GNU_SOURCE

ifeq ($(target),nano)
TOOLCHAIN_PATH=/buildroot/output/host/usr/bin/
TOOLCHAIN=$(TOOLCHAIN_PATH)aarch64-linux-
CFLAGS+=-mcpu=cortex-a53 -funwind-tables
##CFLAGS+=-O2 -fno-omit-frame-pointer
OBJDIR=.obj/nano
EXEC=$(EXE)
endif

ifeq ($(target),host)
EXEC=$(EXE)_h
endif

CC=$(TOOLCHAIN)gcc
LD=$(TOOLCHAIN)gcc
AR=$(TOOLCHAIN)ar
STRIP=$(TOOLCHAIN)strip
OBJDUMP=$(TOOLCHAIN)objdump

OBJDIR=.obj/$(target)
OBJS= $(addprefix $(OBJDIR)/, $(SRCS:.c=.o))

$(OBJDIR)/%o: %c
    $(CC) $(CFLAGS) $< -o $@

all: $(OBJDIR)/ $(EXEC)

$(EXEC): $(OBJS) $(LINKER_SCRIPT)
    $(LD) $(OBJS) $(LDFLAGS) -o $@

$(OBJDIR)/:
    mkdir -p $(OBJDIR)

clean:
    rm -Rf $(OBJDIR) $(EXEC) $(EXEC)_s *~ t.txt

clean_all: clean
    rm -Rf .obj $(EXE) $(EXE)_s $(EXE)_a $(EXE)_a_s $(EXE)_h $(EXE)_h_s

dump: all
    $(OBJDUMP) -dS $(EXEC) > t.txt

-include $(OBJS:.o=.d)

.PHONY: all clean clean_all dump

GCov

main.c

#include <stdio.h>

int main (void)
{
    int res = 1;
    for (int i=0; i<16; i++)
    {
        res *= 2;
    }

    if(res < 10)
    {
        printf("dead code\n");
    }

    printf("res=%d\n", res);

    return 0;
}

Makefile

CC?=gcc
CFLAGS=-std=c11 -Wall -g -fprofile-arcs -ftest-coverage
SOURCES=$(wildcard *.c)
OBJECTS=$(SOURCES:.c=.o)
EXECUTABLE=example-gcov

all: $(SOURCES) $(EXECUTABLE)

$(EXECUTABLE): $(OBJECTS)
    $(CC) $(CFLAGS) -o $@ $(OBJECTS)

.c.o:
    $(CC) -c $(CFLAGS) $< -o $@


clean:
    @rm -f $(OBJECTS)
    @rm -f *.d

clean_all: clean
    @rm -f $(EXECUTABLE)
    @rm -f perf.data perf.data.old
    @rm -f *.gcno *.gcda *.gcov


gcov-generate: all
    ./$(EXECUTABLE)
    gcov main.c

gcov-read: gcov-generate
    less main.c.gcov


-include *.d

GPIO

gpio.c

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sched.h>
#include <sys/mman.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>

#define GPIO_EXPORT     "/sys/class/gpio/export"
#define GPIO_UNEXPORT   "/sys/class/gpio/unexport"
#define GPIO_GPIOG11    "/sys/class/gpio/gpio203"
#define GPIOG11         "203"

static int open_gpio()
{
    // unexport pin out of sysfs (reinitialization)
    int f = open (GPIO_UNEXPORT, O_WRONLY);
    write (f, GPIOG11, strlen(GPIOG11));
    close (f);

    // export pin to sysfs
    f = open (GPIO_EXPORT, O_WRONLY);
    write (f, GPIOG11, strlen(GPIOG11));
    close (f);  

    // config pin
    f = open (GPIO_GPIOG11 "/direction", O_WRONLY);
    write (f, "out", 3);
    close (f);

    // open gpio value attribute
    f = open (GPIO_GPIOG11 "/value", O_RDWR);
    return f;
}

/**
 * main program...
 */
int main()
{
    cpu_set_t my_set;
    CPU_ZERO(&my_set);
    CPU_SET(2, &my_set);
    sched_setaffinity(0, sizeof(cpu_set_t), &my_set);

    int gpio = open_gpio();
    bool on = false;
    struct timespec start_time;
    struct timespec stop_time;
    clock_gettime (CLOCK_MONOTONIC, &start_time);  // setup...


    // --> measurement with internal timers
    clock_gettime (CLOCK_MONOTONIC, &start_time);
    for (int i=0; i<1000; i++) {
        if (on) {
            pwrite (gpio, "1", sizeof("1"), 0);
        } else {
            pwrite (gpio, "0", sizeof("0"), 0);
        }
        on = !on;
    }
    clock_gettime (CLOCK_MONOTONIC, &stop_time);
    long long t = (stop_time.tv_nsec - start_time.tv_nsec) +
            (stop_time.tv_sec - start_time.tv_sec) * 1000000000;
        printf ("pwrite (gpio, \"1\", sizeof(\"1\"), 0) -> %lld ns\n", t/1000);


    // --> measurement with oscilloscope
    while(true) {
        if (on) {
            pwrite (gpio, "1", sizeof("1"), 0);
        } else {
            pwrite (gpio, "0", sizeof("0"), 0);
        }
        on = !on;
    }

    return 0;
}

Makefile

EXE=gpio
SRCS=$(wildcard *.c)

ifeq ($(target),)
target=nano
endif

CFLAGS=-Wall -Wextra -g -c -O1 -MD -std=gnu11 -D_GNU_SOURCE

ifeq ($(target),nano)
TOOLCHAIN_PATH=/buildroot/output/host/usr/bin/
TOOLCHAIN=$(TOOLCHAIN_PATH)aarch64-linux-
CFLAGS+=-mcpu=cortex-a53 -funwind-tables
##CFLAGS+=-O2 -fno-omit-frame-pointer
OBJDIR=.obj/nano
EXEC=$(EXE)
endif

ifeq ($(target),host)
EXEC=$(EXE)_h
endif

ifeq ($(target),xu3)
TOOLCHAIN_PATH=~/workspace/xu3/buildroot/output/host/usr/bin/
TOOLCHAIN=$(TOOLCHAIN_PATH)arm-linux-gnueabihf-
CFLAGS+=-mcpu=cortex-a15.cortex-a7 -funwind-tables
##CFLAGS+=-O2 -fno-omit-frame-pointer
OBJDIR=.obj/xu3
EXEC=$(EXE)_a
endif

CC=$(TOOLCHAIN)gcc
LD=$(TOOLCHAIN)gcc
AR=$(TOOLCHAIN)ar
STRIP=$(TOOLCHAIN)strip
OBJDUMP=$(TOOLCHAIN)objdump

OBJDIR=.obj/$(target)
OBJS= $(addprefix $(OBJDIR)/, $(SRCS:.c=.o))

$(OBJDIR)/%o: %c
    $(CC) $(CFLAGS) $< -o $@

all: $(OBJDIR)/ $(EXEC)

$(EXEC): $(OBJS) $(LINKER_SCRIPT)
    $(LD) $(OBJS) $(LDFLAGS) -o $@

$(OBJDIR)/:
    mkdir -p $(OBJDIR)

clean:
    rm -Rf $(OBJDIR) $(EXEC) $(EXEC)_s *~ t.txt

clean_all: clean
    rm -Rf .obj $(EXE) $(EXE)_s $(EXE)_a $(EXE)_a_s $(EXE)_h $(EXE)_h_s

dump: all
    $(OBJDUMP) -dS $(EXEC) > t.txt

-include $(OBJS:.o=.d)

.PHONY: all clean clean_all dump

GProf

main.c

void func1(void)
{
    for(int i=0; i<0xfffffff; i++); // wait...
    return;
}

void func2(void)
{
    for(int i=0;i<0xfffffff;i++); // wait...
    func1();
    return;
}

int main(void)
{
    for(int i=0;i<0xfffffff;i++);
    func1();
    func2();

    return 0;
}

Makefile

CC?=gcc
CFLAGS=-std=c11 -Wall -pg
SOURCES=$(wildcard *.c)
OBJECTS=$(SOURCES:.c=.o)
EXECUTABLE=example-gprof

all: $(SOURCES) $(EXECUTABLE)

$(EXECUTABLE): $(OBJECTS)
    $(CC) $(CFLAGS) -o $@ $(OBJECTS)

.c.o:
    $(CC) -c $(CFLAGS) $< -o $@


clean:
    @rm -f $(OBJECTS)
    @rm -f *.d

clean_all: clean
    @rm -f $(EXECUTABLE)
    @rm -f perf.data perf.data.old
    @rm -f gmon.out gprof.out


gprof-generate: all
    ./$(EXECUTABLE)
    gprof $(EXECUTABLE) > gprof.out

gprof-read:
    less gprof.out


-include *.d

target.mk

EXE=example-gprof
SRCS=$(wildcard *.c) 

ifeq ($(target),)
target=nano
endif

CFLAGS=-Wall -Wextra -g -c -O1 -MD -std=gnu11 -D_GNU_SOURCE -pg

ifeq ($(target),nano)
TOOLCHAIN_PATH=/buildroot/output/host/usr/bin/
TOOLCHAIN=$(TOOLCHAIN_PATH)aarch64-linux-
CFLAGS+=-mcpu=cortex-a53 -funwind-tables
CFLAGS+=-O2 -fno-omit-frame-pointer
OBJDIR=.obj/nano
EXEC=$(EXE)
endif

ifeq ($(target),host)
EXEC=$(EXE)_h
endif

CC=$(TOOLCHAIN)gcc
LD=$(TOOLCHAIN)gcc
AR=$(TOOLCHAIN)ar
STRIP=$(TOOLCHAIN)strip
OBJDUMP=$(TOOLCHAIN)objdump

OBJDIR=.obj/$(target)
OBJS= $(addprefix $(OBJDIR)/, $(SRCS:.c=.o))

$(OBJDIR)/%o: %c
    $(CC) $(CFLAGS) $< -o $@

all: $(OBJDIR)/ $(EXEC)

$(EXEC): $(OBJS) $(LINKER_SCRIPT)
    $(LD) $(OBJS) $(LDFLAGS) -o $@

$(OBJDIR)/:
    mkdir -p $(OBJDIR)

clean:
    rm -Rf $(OBJDIR) $(EXEC) $(EXEC)_s *~ t.txt

clean_all: clean
    rm -Rf .obj $(EXE) $(EXE)_s $(EXE)_a $(EXE)_a_s $(EXE)_h $(EXE)_h_s
    @rm -f perf.data perf.data.old gmon.out gprof.out

dump: all
    $(OBJDUMP) -dS $(EXEC) > t.txt

gprof-generate: all
    ./$(EXECUTABLE)
    gprof $(EXECUTABLE) > gprof.out

gprof-read:
    less gprof.out

-include $(OBJS:.o=.d)

.PHONY: all clean clean_all dump

MMIO

mmio.c

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sched.h>
#include <sys/mman.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>

#define GPIO_EXPORT     "/sys/class/gpio/export"
#define GPIO_UNEXPORT   "/sys/class/gpio/unexport"
#define GPIO_GPIOG11    "/sys/class/gpio/gpio203"
#define GPIOG11         "203"

static int open_gpio()
{
    // unexport pin out of sysfs (reinitialization)
    int f = open (GPIO_UNEXPORT, O_WRONLY);
    write (f, GPIOG11, strlen(GPIOG11));
    close (f);

    // export pin to sysfs
    f = open (GPIO_EXPORT, O_WRONLY);
    write (f, GPIOG11, strlen(GPIOG11));
    close (f);

    // config pin
    f = open (GPIO_GPIOG11 "/direction", O_WRONLY);
    write (f, "out", 3);
    close (f);

    // open gpio value attribute
    f = open (GPIO_GPIOG11 "/value", O_RDWR);
    return f;
}

/**
 * main program...
 */
int main()
{
    cpu_set_t my_set;
    CPU_ZERO(&my_set);
    CPU_SET(2, &my_set);
    sched_setaffinity(0, sizeof(cpu_set_t), &my_set);

    int gpio = open_gpio();
    pwrite (gpio, "1", sizeof("1"), 0);
    pwrite (gpio, "0", sizeof("0"), 0);

    int fd = open ("/dev/mem", O_RDWR);
    if (fd == -1) return -1;
    off_t psz = getpagesize();
    volatile uint32_t*  pio = mmap (0, psz, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x01c20000);
    volatile uint32_t* dat_pio  =  pio + (0x810+6*0x24)/4;

    struct timespec start_time;
    struct timespec stop_time;
    clock_gettime (CLOCK_MONOTONIC, &start_time);  // setup...

    // --> measurement with internal timers on gpio
    clock_gettime (CLOCK_MONOTONIC, &start_time);

    for (int i=0; i<1000; i++)
        *dat_pio ^= (1<<11);

    clock_gettime (CLOCK_MONOTONIC, &stop_time);
    long long t = (stop_time.tv_nsec - start_time.tv_nsec) +
            (stop_time.tv_sec - start_time.tv_sec) * 1000000000;
    printf ("*dat_pio ^= (1<<11) --> %6lld ns\n", t/1000);


    // --> measurement on internal data with internal timers
    volatile uint32_t data = 0;
    clock_gettime (CLOCK_MONOTONIC, &start_time);

    for (int i=0; i<1000; i++)
        data ^= (1<<12);

    clock_gettime (CLOCK_MONOTONIC, &stop_time);
    t = (stop_time.tv_nsec - start_time.tv_nsec) +
            (stop_time.tv_sec - start_time.tv_sec) * 1000000000;
    printf ("data     ^= (1<<11) --> %6lld ns\n", t/1000);


    // --> measurement with oscilloscope
    while(true) {
        *dat_pio ^= (1<<11);
    }

    return 0;
}

Makefile

EXE=mmio
SRCS=$(wildcard *.c)

ifeq ($(target),)
target=nano
endif

CFLAGS=-Wall -Wextra -g -c -O1 -MD -std=gnu11 -D_GNU_SOURCE

ifeq ($(target),nano)
TOOLCHAIN_PATH=/buildroot/output/host/usr/bin/
TOOLCHAIN=$(TOOLCHAIN_PATH)aarch64-linux-
CFLAGS+=-mcpu=cortex-a53 -funwind-tables
##CFLAGS+=-O2 -fno-omit-frame-pointer
OBJDIR=.obj/nano
EXEC=$(EXE)
endif

ifeq ($(target),host)
EXEC=$(EXE)_h
endif

CC=$(TOOLCHAIN)gcc
LD=$(TOOLCHAIN)gcc
AR=$(TOOLCHAIN)ar
STRIP=$(TOOLCHAIN)strip
OBJDUMP=$(TOOLCHAIN)objdump

OBJDIR=.obj/$(target)
OBJS= $(addprefix $(OBJDIR)/, $(SRCS:.c=.o))

$(OBJDIR)/%o: %c
    $(CC) $(CFLAGS) $< -o $@

all: $(OBJDIR)/ $(EXEC)

$(EXEC): $(OBJS) $(LINKER_SCRIPT)
    $(LD) $(OBJS) $(LDFLAGS) -o $@

$(OBJDIR)/:
    mkdir -p $(OBJDIR)

clean:
    rm -Rf $(OBJDIR) $(EXEC) $(EXEC)_s *~ t.txt

clean_all: clean
    rm -Rf .obj $(EXE) $(EXE)_s $(EXE)_a $(EXE)_a_s $(EXE)_h $(EXE)_h_s

dump: all
    $(OBJDUMP) -dS $(EXEC) > t.txt

-include $(OBJS:.o=.d)

.PHONY: all clean clean_all dump

Trace

main.c

#include <unistd.h>

int main()
{
    while(1)
        sleep(1);
    return 0;
}

Makefile

EXE=tracing
SRCS=$(wildcard *.c)

ifeq ($(target),)
target=nano
endif

CFLAGS=-Wall -Wextra -g -c -O1 -MD -std=gnu11 -D_GNU_SOURCE

ifeq ($(target),nano)
TOOLCHAIN_PATH=/buildroot/output/host/usr/bin/
TOOLCHAIN=$(TOOLCHAIN_PATH)aarch64-linux-
CFLAGS+=-mcpu=cortex-a53 -funwind-tables
##CFLAGS+=-O2 -fno-omit-frame-pointer
OBJDIR=.obj/nano
EXEC=$(EXE)
endif

ifeq ($(target),host)
EXEC=$(EXE)_h
endif

CC=$(TOOLCHAIN)gcc
LD=$(TOOLCHAIN)gcc
AR=$(TOOLCHAIN)ar
STRIP=$(TOOLCHAIN)strip
OBJDUMP=$(TOOLCHAIN)objdump

OBJDIR=.obj/$(target)
OBJS= $(addprefix $(OBJDIR)/, $(SRCS:.c=.o))

$(OBJDIR)/%o: %c
    $(CC) $(CFLAGS) $< -o $@

all: $(OBJDIR)/ $(EXEC)

$(EXEC): $(OBJS) $(LINKER_SCRIPT)
    $(LD) $(OBJS) $(LDFLAGS) -o $@

$(OBJDIR)/:
    mkdir -p $(OBJDIR)

clean:
    rm -Rf $(OBJDIR) $(EXEC) $(EXEC)_s *~ t.txt

clean_all: clean
    rm -Rf .obj $(EXE) $(EXE)_s $(EXE)_a $(EXE)_a_s $(EXE)_h $(EXE)_h_s

dump: all
    $(OBJDUMP) -dS $(EXEC) > t.txt

-include $(OBJS:.o=.d)

.PHONY: all clean clean_all dump

setup.sh

mount -t debugfs nodev /sys/kernel/debug

example1.sh

#!/bin/sh
# 1. example
echo 1 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable
./tracing  &
pidof tracing > /sys/kernel/debug/tracing/set_event_pid
echo 1 > /sys/kernel/debug/tracing/tracing_on ; sleep 2 ; echo 0 > /sys/kernel/debug/tracing/tracing_on
trace-cmd show

example2.sh

#!/bin/sh
# 2. example
echo function_graph > /sys/kernel/debug/tracing/current_tracer
echo *i2c* >  /sys/kernel/debug/tracing/set_ftrace_filter
echo 1 >  /sys/kernel/debug/tracing/tracing_on
i2cdetect -y 0
echo 0 >  /sys/kernel/debug/tracing/tracing_on
trace-cmd show
echo nop > /sys/kernel/debug/tracing/current_tracer