我看到太多的链接显示strace在其输出中将gettimeofday列为系统调用，但就我而言，我感觉它已分解为其他调用。我想念什么吗？

我正在Linux 4.4内核和ubuntu 16.04上的VM中运行

root@ak-dev-1:~# cat trial.c && gcc trial.c && strace -c ./a.out
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>

int main() {
    struct timeval tv;
    gettimeofday(&tv,NULL);
    printf("%lu.%lu\n",tv.tv_sec,tv.tv_usec);
}
1584465316.623916
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
  0.00    0.000000           0         1           read
  0.00    0.000000           0         1           write
  0.00    0.000000           0         2           open
  0.00    0.000000           0         2           close
  0.00    0.000000           0         3           fstat
  0.00    0.000000           0         7           mmap
  0.00    0.000000           0         4           mprotect
  0.00    0.000000           0         1           munmap
  0.00    0.000000           0         3           brk
  0.00    0.000000           0         3         3 access
  0.00    0.000000           0         1           execve
  0.00    0.000000           0         1           arch_prctl
------ ----------- ----------- --------- --------- ----------------
100.00    0.000000                    29         3 total


root@ak-dev-1:~# uname -a
Linux ak-dev-1 4.4.0-137-generic #163-Ubuntu SMP Mon Sep 24 13:14:43 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux