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 <algorithm>
18 #include <chrono>
19 #include <thread>
20 #include <vector>
21
22 #include <sys/capability.h>
23
24 #include <cutils/sched_policy.h>
25
26 #include <gtest/gtest.h>
27
hasCapSysNice()28 bool hasCapSysNice() {
29 __user_cap_header_struct header;
30 memset(&header, 0, sizeof(header));
31 header.version = _LINUX_CAPABILITY_VERSION_3;
32
33 __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3];
34 if (capget(&header, &caps[0])) {
35 GTEST_LOG_(WARNING) << "failed to get process capabilities";
36 return false;
37 }
38
39 auto nice_idx = CAP_TO_INDEX(CAP_SYS_NICE);
40 auto nice_mask = CAP_TO_MASK(CAP_SYS_NICE);
41 return caps[nice_idx].effective & nice_mask;
42 }
43
medianSleepTime()44 long long medianSleepTime() {
45 std::vector<long long> sleepTimes;
46 constexpr size_t numSamples = 100;
47
48 for (size_t i = 0; i < numSamples; i++) {
49 auto start = std::chrono::steady_clock::now();
50 std::this_thread::sleep_for(std::chrono::nanoseconds(1));
51 auto end = std::chrono::steady_clock::now();
52
53 auto diff = end - start;
54 sleepTimes.push_back(diff.count());
55 }
56
57 constexpr auto median = numSamples / 2;
58 std::nth_element(sleepTimes.begin(), sleepTimes.begin() + median,
59 sleepTimes.end());
60 return sleepTimes[median];
61 }
62
AssertPolicy(SchedPolicy expected_policy)63 static void AssertPolicy(SchedPolicy expected_policy) {
64 SchedPolicy current_policy;
65 ASSERT_EQ(0, get_sched_policy(0, ¤t_policy));
66 EXPECT_EQ(expected_policy, current_policy);
67 }
68
TEST(SchedPolicy,set_sched_policy)69 TEST(SchedPolicy, set_sched_policy) {
70 if (!schedboost_enabled()) {
71 // schedboost_enabled() (i.e. CONFIG_CGROUP_SCHEDTUNE) is optional;
72 // it's only needed on devices using energy-aware scheduler.
73 GTEST_LOG_(INFO) << "skipping test that requires CONFIG_CGROUP_SCHEDTUNE";
74 return;
75 }
76
77 ASSERT_EQ(0, set_sched_policy(0, SP_BACKGROUND));
78 AssertPolicy(SP_BACKGROUND);
79
80 ASSERT_EQ(0, set_sched_policy(0, SP_FOREGROUND));
81 AssertPolicy(SP_FOREGROUND);
82 }
83
TEST(SchedPolicy,set_sched_policy_timerslack)84 TEST(SchedPolicy, set_sched_policy_timerslack) {
85 if (!hasCapSysNice()) {
86 GTEST_LOG_(INFO) << "skipping test that requires CAP_SYS_NICE";
87 return;
88 }
89
90 // A measureable effect of scheduling policy is that the kernel has 800x
91 // greater slack time in waking up a sleeping background thread.
92 //
93 // Look for 10x difference in how long FB and BG threads actually sleep
94 // when trying to sleep for 1 ns. This difference is large enough not
95 // to happen by chance, but small enough (compared to 800x) to keep inherent
96 // fuzziness in scheduler behavior from causing false negatives.
97 const unsigned int BG_FG_SLACK_FACTOR = 10;
98
99 ASSERT_EQ(0, set_sched_policy(0, SP_BACKGROUND));
100 auto bgSleepTime = medianSleepTime();
101
102 ASSERT_EQ(0, set_sched_policy(0, SP_FOREGROUND));
103 auto fgSleepTime = medianSleepTime();
104
105 ASSERT_GT(bgSleepTime, fgSleepTime * BG_FG_SLACK_FACTOR);
106 }
107
TEST(SchedPolicy,get_sched_policy_name)108 TEST(SchedPolicy, get_sched_policy_name) {
109 EXPECT_STREQ("bg", get_sched_policy_name(SP_BACKGROUND));
110 EXPECT_EQ(nullptr, get_sched_policy_name(SchedPolicy(-2)));
111 EXPECT_EQ(nullptr, get_sched_policy_name(SP_CNT));
112 }
113
TEST(SchedPolicy,get_cpuset_policy_profile_name)114 TEST(SchedPolicy, get_cpuset_policy_profile_name) {
115 EXPECT_STREQ("CPUSET_SP_BACKGROUND", get_cpuset_policy_profile_name(SP_BACKGROUND));
116 EXPECT_EQ(nullptr, get_cpuset_policy_profile_name(SchedPolicy(-2)));
117 EXPECT_EQ(nullptr, get_cpuset_policy_profile_name(SP_CNT));
118 }
119
TEST(SchedPolicy,get_sched_policy_profile_name)120 TEST(SchedPolicy, get_sched_policy_profile_name) {
121 EXPECT_STREQ("SCHED_SP_BACKGROUND", get_sched_policy_profile_name(SP_BACKGROUND));
122 EXPECT_EQ(nullptr, get_sched_policy_profile_name(SchedPolicy(-2)));
123 EXPECT_EQ(nullptr, get_sched_policy_profile_name(SP_CNT));
124 }
125