系統 - Debian - Performance - 如何使用Perf Probe

參考資訊：
https://www.brendangregg.com/perf.html
https://docs.kernel.org/trace/uprobetracer.html
https://bristot.me/using-perf-probe-to-measure-execution-time-of-user-space-code-on-linux/

main.c

#include <stdio.h>

void test(void)
{
    printf("hello\n");
}

int main(int argc, char *argv[])
{
    test();
    return 0;
}

編譯

$ gcc main.c -o main -ggdb -O0

Probe方式1

$ sudo perf probe --line test -x ./main
    <test@main.c:0>
          0  void test(void)
             {
          2      printf("hello\n");
          3  }
              
$ sudo perf probe -x ./main 'myprobe=test:0'
$ sudo perf stat -e probe_main:* ./main
     Performance counter stats for './main':
                     1      probe_main:myprobe                                                 

$ sudo perf probe --del probe_main:*
    Removed event: probe_main:myprobe

Probe方式2

$ nm main | grep test
    0000000000001139 T test

$ sudo perf probe -x ./main -a myprobe=0x1139
$ sudo perf stat -e probe_main:* ./main
     Performance counter stats for './main':
                     1      probe_main:myprobe                                                 

$ sudo perf probe --del probe_main:*
    Removed event: probe_main:myprobe

Probe方式3

$ nm main | grep test
    0000000000001139 T test

$ su
# echo 'p:myprobe ./main:0x1139' > /sys/kernel/tracing/uprobe_events
# echo 1 > /sys/kernel/tracing/events/uprobes/myprobe/enable
# ./main 
    hello

# tail /sys/kernel/tracing/trace
#
#                                _-----=> irqs-off/BH-disabled
#                               / _----=> need-resched
#                              | / _---=> hardirq/softirq
#                              || / _--=> preempt-depth
#                              ||| / _-=> migrate-disable
#                              |||| /     delay
#           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
#              | |         |   |||||     |         |
            main-41148   [000] DNZff 10856.113989: myprobe: (0x55fc66688139)

# cat /sys/kernel/tracing/uprobe_events 
    p:uprobes/myprobe ./main:0x0000000000001139

# echo 0 > /sys/kernel/tracing/events/uprobes/myprobe/enable
# echo "" > /sys/kernel/tracing/uprobe_events