tools/testing/selftests/timens/gettime_perf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define _GNU_SOURCE
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <errno.h>
   6 #include <fcntl.h>
   7 #include <sched.h>
   8 #include <time.h>
   9 #include <stdio.h>
  10 #include <unistd.h>
  11 #include <sys/syscall.h>
  12 #include <dlfcn.h>
  13
  14 #include "log.h"
  15 #include "timens.h"
  16
  17 typedef int (*vgettime_t)(clockid_t, struct timespec *);
  18
  19 vgettime_t vdso_clock_gettime;
  20
  21 static void fill_function_pointers(void)
  22 {
  23         void *vdso = dlopen("linux-vdso.so.1",
  24                             RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  25         if (!vdso)
  26                 vdso = dlopen("linux-gate.so.1",
  27                               RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  28         if (!vdso) {
  29                 pr_err("[WARN]\tfailed to find vDSO\n");
  30                 return;
  31         }
  32
  33         vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");
  34         if (!vdso_clock_gettime)
  35                 pr_err("Warning: failed to find clock_gettime in vDSO\n");
  36
  37 }
  38
  39 static void test(clock_t clockid, char *clockstr, bool in_ns)
  40 {
  41         struct timespec tp, start;
  42         long i = 0;
  43         const int timeout = 3;
  44
  45         vdso_clock_gettime(clockid, &start);
  46         tp = start;
  47         for (tp = start; start.tv_sec + timeout > tp.tv_sec ||
  48                          (start.tv_sec + timeout == tp.tv_sec &&
  49                           start.tv_nsec > tp.tv_nsec); i++) {
  50                 vdso_clock_gettime(clockid, &tp);
  51         }
  52
  53         ksft_test_result_pass("%s:\tclock: %10s\tcycles:\t%10ld\n",
  54                               in_ns ? "ns" : "host", clockstr, i);
  55 }
  56
  57 int main(int argc, char *argv[])
  58 {
  59         time_t offset = 10;
  60         int nsfd;
  61
  62         ksft_set_plan(8);
  63
  64         fill_function_pointers();
  65
  66         test(CLOCK_MONOTONIC, "monotonic", false);
  67         test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", false);
  68         test(CLOCK_MONOTONIC_RAW, "monotonic-raw", false);
  69         test(CLOCK_BOOTTIME, "boottime", false);
  70
  71         nscheck();
  72
  73         if (unshare_timens())
  74                 return 1;
  75
  76         nsfd = open("/proc/self/ns/time_for_children", O_RDONLY);
  77         if (nsfd < 0)
  78                 return pr_perror("Can't open a time namespace");
  79
  80         if (_settime(CLOCK_MONOTONIC, offset))
  81                 return 1;
  82         if (_settime(CLOCK_BOOTTIME, offset))
  83                 return 1;
  84
  85         if (setns(nsfd, CLONE_NEWTIME))
  86                 return pr_perror("setns");
  87
  88         test(CLOCK_MONOTONIC, "monotonic", true);
  89         test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", true);
  90         test(CLOCK_MONOTONIC_RAW, "monotonic-raw", true);
  91         test(CLOCK_BOOTTIME, "boottime", true);
  92
  93         ksft_exit_pass();
  94         return 0;
  95 }