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 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
