Date: Thu, 16 Apr 2020 22:38:06 -0500 From: Kyle Evans <kevans@freebsd.org> To: Ian Lepore <ian@freebsd.org> Cc: src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r360033 - head/tests/sys/kqueue/libkqueue Message-ID: <CACNAnaHbGdUH0QkdJpz8%2B_q6W4rHG3xgySe1OJ209i505Mhe8w@mail.gmail.com> In-Reply-To: <28f9262a36dc4b7d4437ef3860ac8e472f6df2ff.camel@freebsd.org> References: <202004170222.03H2MFso026451@repo.freebsd.org> <28f9262a36dc4b7d4437ef3860ac8e472f6df2ff.camel@freebsd.org>
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On Thu, Apr 16, 2020 at 9:33 PM Ian Lepore <ian@freebsd.org> wrote: > > On Fri, 2020-04-17 at 02:22 +0000, Kyle Evans wrote: > > 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(); > > Not caused by you, but this change made me notice: using 'long' to > hold the number of microseconds since the unix epoch will only work on > amd64 and arm64. Everything involved with that needs to use uint64_t > to work on all arches. > > -- Ian > Good point, I'll go fix that after arichardson's in-flight change near these tests lands. Thanks, Kyle Evans
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