selftests/timens: Add a simple perf test for clock_gettime()

Output on success:
1..4
 ok 1 host:	clock:  monotonic	cycles:	 148323947
 ok 2 host:	clock:   boottime	cycles:	 148577503
 ok 3 ns:	clock:  monotonic	cycles:	 137659217
 ok 4 ns:	clock:   boottime	cycles:	 137959154
 # Pass 4 Fail 0 Xfail 0 Xpass 0 Skip 0 Error 0

Output with lack of permissions:
 1..4
 ok 1 host:	clock:  monotonic	cycles:	 145671139
 ok 2 host:	clock:   boottime	cycles:	 146958357
 not ok 3 # SKIP need to run as root

Output without support of time namespaces:
 1..4
 ok 1 host:	clock:  monotonic	cycles:	 145671139
 ok 2 host:	clock:   boottime	cycles:	 146958357
 not ok 3 # SKIP Time namespaces are not supported

Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-34-dima@arista.com

diff --git a/tools/testing/selftests/timens/.gitignore b/tools/testing/selftests/timens/.gitignore
index 3b7eda8..16292e4 100644 (file)
--- a/tools/testing/selftests/timens/.gitignore
+++ b/tools/testing/selftests/timens/.gitignore
@@ -1,4 +1,6 @@
 clock_nanosleep
+gettime_perf
+gettime_perf_cold
 procfs
 timens
 timer

diff --git a/tools/testing/selftests/timens/Makefile b/tools/testing/selftests/timens/Makefile
index 0816454..6aefcac 100644 (file)
--- a/tools/testing/selftests/timens/Makefile
+++ b/tools/testing/selftests/timens/Makefile
@@ -1,6 +1,7 @@
 TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs
+TEST_GEN_PROGS_EXTENDED := gettime_perf
 
 CFLAGS := -Wall -Werror -pthread
-LDFLAGS := -lrt
+LDFLAGS := -lrt -ldl
 
 include ../lib.mk

diff --git a/tools/testing/selftests/timens/gettime_perf.c b/tools/testing/selftests/timens/gettime_perf.c
new file mode 100644 (file)
index 0000000..7bf841a
--- /dev/null
+++ b/tools/testing/selftests/timens/gettime_perf.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <time.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <dlfcn.h>
+
+#include "log.h"
+#include "timens.h"
+
+typedef int (*vgettime_t)(clockid_t, struct timespec *);
+
+vgettime_t vdso_clock_gettime;
+
+static void fill_function_pointers(void)
+{
+       void *vdso = dlopen("linux-vdso.so.1",
+                           RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+       if (!vdso)
+               vdso = dlopen("linux-gate.so.1",
+                             RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+       if (!vdso) {
+               pr_err("[WARN]\tfailed to find vDSO\n");
+               return;
+       }
+
+       vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");
+       if (!vdso_clock_gettime)
+               pr_err("Warning: failed to find clock_gettime in vDSO\n");
+
+}
+
+static void test(clock_t clockid, char *clockstr, bool in_ns)
+{
+       struct timespec tp, start;
+       long i = 0;
+       const int timeout = 3;
+
+       vdso_clock_gettime(clockid, &start);
+       tp = start;
+       for (tp = start; start.tv_sec + timeout > tp.tv_sec ||
+                        (start.tv_sec + timeout == tp.tv_sec &&
+                         start.tv_nsec > tp.tv_nsec); i++) {
+               vdso_clock_gettime(clockid, &tp);
+       }
+
+       ksft_test_result_pass("%s:\tclock: %10s\tcycles:\t%10ld\n",
+                             in_ns ? "ns" : "host", clockstr, i);
+}
+
+int main(int argc, char *argv[])
+{
+       time_t offset = 10;
+       int nsfd;
+
+       ksft_set_plan(8);
+
+       fill_function_pointers();
+
+       test(CLOCK_MONOTONIC, "monotonic", false);
+       test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", false);
+       test(CLOCK_MONOTONIC_RAW, "monotonic-raw", false);
+       test(CLOCK_BOOTTIME, "boottime", false);
+
+       nscheck();
+
+       if (unshare_timens())
+               return 1;
+
+       nsfd = open("/proc/self/ns/time_for_children", O_RDONLY);
+       if (nsfd < 0)
+               return pr_perror("Can't open a time namespace");
+
+       if (_settime(CLOCK_MONOTONIC, offset))
+               return 1;
+       if (_settime(CLOCK_BOOTTIME, offset))
+               return 1;
+
+       if (setns(nsfd, CLONE_NEWTIME))
+               return pr_perror("setns");
+
+       test(CLOCK_MONOTONIC, "monotonic", true);
+       test(CLOCK_MONOTONIC_COARSE, "monotonic-coarse", true);
+       test(CLOCK_MONOTONIC_RAW, "monotonic-raw", true);
+       test(CLOCK_BOOTTIME, "boottime", true);
+
+       ksft_exit_pass();
+       return 0;
+}