xref: /openbsd-src/gnu/usr.bin/perl/dist/Time-HiRes/t/clock.t (revision 56d68f1e19ff848c889ecfa71d3a06340ff64892)
1use strict;
2
3use Test::More tests => 5;
4BEGIN { push @INC, '.' }
5use t::Watchdog;
6
7BEGIN { require_ok "Time::HiRes"; }
8
9sub has_symbol {
10    my $symbol = shift;
11    eval "use Time::HiRes qw($symbol)";
12    return 0 unless $@ eq '';
13    eval "my \$a = $symbol";
14    return $@ eq '';
15}
16
17printf("# have_clock_gettime   = %d\n", &Time::HiRes::d_clock_gettime);
18printf("# have_clock_getres    = %d\n", &Time::HiRes::d_clock_getres);
19printf("# have_clock_nanosleep = %d\n", &Time::HiRes::d_clock_nanosleep);
20printf("# have_clock           = %d\n", &Time::HiRes::d_clock);
21
22# Ideally, we'd like to test that the timers are rather precise.
23# However, if the system is busy, there are no guarantees on how
24# quickly we will return.  This limit used to be 10%, but that
25# was occasionally triggered falsely.
26# So let's try 25%.
27# Another possibility might be to print "ok" if the test completes fine
28# with (say) 10% slosh, "skip - system may have been busy?" if the test
29# completes fine with (say) 30% slosh, and fail otherwise.  If you do that,
30# consider changing over to test.pl at the same time.
31# --A.D., Nov 27, 2001
32my $limit = 0.25; # 25% is acceptable slosh for testing timers
33
34SKIP: {
35    skip "no clock_gettime", 1
36        unless &Time::HiRes::d_clock_gettime && has_symbol("CLOCK_REALTIME");
37    my $ok = 0;
38 TRY: {
39        for my $try (1..3) {
40            print("# CLOCK_REALTIME: try = $try\n");
41            my $t0 = Time::HiRes::clock_gettime(&CLOCK_REALTIME);
42            my $T = 1.5;
43            Time::HiRes::sleep($T);
44            my $t1 = Time::HiRes::clock_gettime(&CLOCK_REALTIME);
45            if ($t0 > 0 && $t1 > $t0) {
46                print("# t1 = $t1, t0 = $t0\n");
47                my $dt = $t1 - $t0;
48                my $rt = abs(1 - $dt / $T);
49                print("# dt = $dt, rt = $rt\n");
50                if ($rt <= 2 * $limit) {
51                    $ok = 1;
52                    last TRY;
53                }
54            } else {
55                print("# Error: t0 = $t0, t1 = $t1\n");
56            }
57            my $r = rand() + rand();
58            printf("# Sleeping for %.6f seconds...\n", $r);
59            Time::HiRes::sleep($r);
60        }
61    }
62    ok $ok;
63}
64
65SKIP: {
66    skip "no clock_getres", 1 unless &Time::HiRes::d_clock_getres;
67    my $tr = Time::HiRes::clock_getres();
68    ok $tr > 0 or print("# tr = $tr\n");
69}
70
71SKIP: {
72    skip "no clock_nanosleep", 1
73        unless &Time::HiRes::d_clock_nanosleep && has_symbol("CLOCK_REALTIME");
74    my $s = 1.5e9;
75    my $t = Time::HiRes::clock_nanosleep(&CLOCK_REALTIME, $s);
76    my $r = abs(1 - $t / $s);
77    ok $r < 2 * $limit or print("# t = $t, r = $r\n");
78}
79
80SKIP: {
81    skip "no clock", 1 unless &Time::HiRes::d_clock;
82    skip "no CLOCKS_PER_SEC", 1 unless has_symbol("CLOCKS_PER_SEC");
83    my @clock = Time::HiRes::clock();
84    # If we have a relatively low precision clock() and we haven't seen much
85    # CPU usage thus far with clock(), we will want to have a bit longer delay.
86    my $delay = $clock[0] < (5 / &Time::HiRes::CLOCKS_PER_SEC) ? 1e7 : 1e6;
87    printf("# CLOCKS_PER_SEC = %d\n", &Time::HiRes::CLOCKS_PER_SEC);
88    printf("# delay = %d\n", $delay);
89    print("# clock = @clock\n");
90    for my $i (1..3) {
91        for (my $j = 0; $j < $delay; $j++) { }
92        push @clock, Time::HiRes::clock();
93        print("# clock = @clock\n");
94    }
95    ok $clock[0] >= 0 &&
96        $clock[1] > $clock[0] &&
97        $clock[2] > $clock[1] &&
98        $clock[3] > $clock[2];
99}
100
1011;
102