1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <unistd.h>
18 #include <utils/SystemClock.h>
19
20 #include <gtest/gtest.h>
21
22 static const auto MS_IN_NS = 1000000;
23
24 static const int64_t SLEEP_MS = 500;
25 static const int64_t SLEEP_NS = SLEEP_MS * MS_IN_NS;
26 // Conservatively assume that we might be descheduled for up to 50 ms
27 static const int64_t SLACK_MS = 50;
28 static const int64_t SLACK_NS = SLACK_MS * MS_IN_NS;
29
TEST(SystemClock,SystemClock)30 TEST(SystemClock, SystemClock) {
31 auto startUptimeMs = android::uptimeMillis();
32 auto startRealtimeMs = android::elapsedRealtime();
33 auto startRealtimeNs = android::elapsedRealtimeNano();
34
35 ASSERT_GT(startUptimeMs, 0)
36 << "uptimeMillis() reported an impossible uptime";
37 ASSERT_GE(startRealtimeMs, startUptimeMs)
38 << "elapsedRealtime() thinks we've suspended for negative time";
39 ASSERT_GE(startRealtimeNs, startUptimeMs * MS_IN_NS)
40 << "elapsedRealtimeNano() thinks we've suspended for negative time";
41
42 ASSERT_GE(startRealtimeNs, startRealtimeMs * MS_IN_NS)
43 << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent";
44 ASSERT_LT(startRealtimeNs, (startRealtimeMs + SLACK_MS) * MS_IN_NS)
45 << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent";
46
47 timespec ts;
48 ts.tv_sec = 0;
49 ts.tv_nsec = SLEEP_MS * MS_IN_NS;
50 auto nanosleepErr = TEMP_FAILURE_RETRY(nanosleep(&ts, nullptr));
51 ASSERT_EQ(nanosleepErr, 0) << "nanosleep() failed: " << strerror(errno);
52
53 auto endUptimeMs = android::uptimeMillis();
54 auto endRealtimeMs = android::elapsedRealtime();
55 auto endRealtimeNs = android::elapsedRealtimeNano();
56
57 EXPECT_GE(endUptimeMs - startUptimeMs, SLEEP_MS)
58 << "uptimeMillis() advanced too little after nanosleep()";
59 EXPECT_LT(endUptimeMs - startUptimeMs, SLEEP_MS + SLACK_MS)
60 << "uptimeMillis() advanced too much after nanosleep()";
61 EXPECT_GE(endRealtimeMs - startRealtimeMs, SLEEP_MS)
62 << "elapsedRealtime() advanced too little after nanosleep()";
63 EXPECT_LT(endRealtimeMs - startRealtimeMs, SLEEP_MS + SLACK_MS)
64 << "elapsedRealtime() advanced too much after nanosleep()";
65 EXPECT_GE(endRealtimeNs - startRealtimeNs, SLEEP_NS)
66 << "elapsedRealtimeNano() advanced too little after nanosleep()";
67 EXPECT_LT(endRealtimeNs - startRealtimeNs, SLEEP_NS + SLACK_NS)
68 << "elapsedRealtimeNano() advanced too much after nanosleep()";
69
70 EXPECT_GE(endRealtimeNs, endRealtimeMs * MS_IN_NS)
71 << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent after nanosleep()";
72 EXPECT_LT(endRealtimeNs, (endRealtimeMs + SLACK_MS) * MS_IN_NS)
73 << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent after nanosleep()";
74 }
75