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                 vdso = dlopen("linux-vdso32.so.1",
  30                               RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  31         if (!vdso)
  32                 vdso = dlopen("linux-vdso64.so.1",
  33                               RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  34         if (!vdso) {
  35                 pr_err("[WARN]\tfailed to find vDSO\n");
  36                 return;
  37         }
  38
  39         vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");
  40         if (!vdso_clock_gettime)
  41                 vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__kernel_clock_gettime");
  42         if (!vdso_clock_gettime)
  43                 pr_err("Warning: failed to find clock_gettime in vDSO\n");
  44
  45 }
  46
  47 static void test(clock_t clockid, char *clockstr, bool in_ns)
  48 {
  49         struct timespec tp, start;
  50         long i = 0;
  51         const int timeout = 3;
  52
  53         vdso_clock_gettime(clockid, &start);
  54         tp = start;
  55         for (tp = start; start.tv_sec + timeout > tp.tv_sec ||
  56                          (start.tv_sec + timeout == tp.tv_sec &&
  57                           start.tv_nsec > tp.tv_nsec); i++) {
  58                 vdso_clock_gettime(clockid, &tp);
  59         }
  60
  61         ksft_test_result_pass("%s:\tclock: %10s\tcycles:\t%10ld\n",
  62                               in_ns ? "ns" : "host", clockstr, i);
  63 }
  64
  65 int main(int argc, char *argv[])
  66 {
  67         time_t offset = 10;
  68         int nsfd;
  69
  70         ksft_set_plan(8);
  71
  72         fill_function_pointers();
  73
  74         test(CLOCK_MONOTONIC, "monotonic", false);
  75         test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", false);
  76         test(CLOCK_MONOTONIC_RAW, "monotonic-raw", false);
  77         test(CLOCK_BOOTTIME, "boottime", false);
  78
  79         nscheck();
  80
  81         if (unshare_timens())
  82                 return 1;
  83
  84         nsfd = open("/proc/self/ns/time_for_children", O_RDONLY);
  85         if (nsfd < 0)
  86                 return pr_perror("Can't open a time namespace");
  87
  88         if (_settime(CLOCK_MONOTONIC, offset))
  89                 return 1;
  90         if (_settime(CLOCK_BOOTTIME, offset))
  91                 return 1;
  92
  93         if (setns(nsfd, CLONE_NEWTIME))
  94                 return pr_perror("setns");
  95
  96         test(CLOCK_MONOTONIC, "monotonic", true);
  97         test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", true);
  98         test(CLOCK_MONOTONIC_RAW, "monotonic-raw", true);
  99         test(CLOCK_BOOTTIME, "boottime", true);
 100
 101         ksft_exit_pass();
 102         return 0;
 103 }