svn commit: r360033 - head/tests/sys/kqueue/libkqueue

[Kyle Evans]

Author: kevans
Date: Fri Apr 17 02:22:15 2020
New Revision: 360033
URL: https://svnweb.freebsd.org/changeset/base/360033

Log:
  tests: kqueue: use a more precise timer for the NOTE_ABSTIME test
  
  Originally noticed while attempting to run the kqueue tests under
  qemu-user-static, this apparently just happens sometimes when running in a
  jail in general -- the timer will fire off "too early," but it's really just
  the result of imprecise measurements (noted by cem).
  
  Kicking this over to NOTE_USECONDS still tests the correct thing while
  allowing it to work more consistently; a basic sanity test reveals that we
  often end up coming in just less than 200 microseconds after the timer
  fired off.
  
  MFC after:	3 days

Modified:
  head/tests/sys/kqueue/libkqueue/timer.c

Modified: head/tests/sys/kqueue/libkqueue/timer.c
==============================================================================
--- head/tests/sys/kqueue/libkqueue/timer.c	Fri Apr 17 02:21:46 2020	(r360032)
+++ head/tests/sys/kqueue/libkqueue/timer.c	Fri Apr 17 02:22:15 2020	(r360033)
@@ -216,17 +216,17 @@ test_abstime(void)
 {
     const char *test_id = "kevent(EVFILT_TIMER, EV_ONESHOT, NOTE_ABSTIME)";
     struct kevent kev;
-    time_t start;
-    time_t stop;
-    const int timeout = 3;
+    long end, start, stop;
+    const int timeout_sec = 3;
 
     test_begin(test_id);
 
     test_no_kevents();
 
-    start = time(NULL);
+    start = now();
+    end = start + SEC_TO_US(timeout_sec);
     EV_SET(&kev, vnode_fd, EVFILT_TIMER, EV_ADD | EV_ONESHOT,
-      NOTE_ABSTIME | NOTE_SECONDS, start + timeout, NULL);
+      NOTE_ABSTIME | NOTE_USECONDS, end, NULL);
     if (kevent(kqfd, &kev, 1, NULL, 0, NULL) < 0)
         err(1, "%s", test_id);
 
@@ -235,10 +235,10 @@ test_abstime(void)
     kev.data = 1;
     kev.fflags = 0;
     kevent_cmp(&kev, kevent_get(kqfd));
-    stop = time(NULL);
-    if (stop < start + timeout)
-        err(1, "too early %jd %jd", (intmax_t)stop, (intmax_t)(start + timeout));
 
+    stop = now();
+    if (stop < end)
+        err(1, "too early %jd %jd", (intmax_t)stop, (intmax_t)end);
     /* Check if the event occurs again */
     sleep(3);
     test_no_kevents();