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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <algorithm>
#include <chrono>
#include <thread>
#include <vector>
#include <sys/capability.h>
#include <cutils/sched_policy.h>
#include <gtest/gtest.h>
bool hasCapSysNice() {
__user_cap_header_struct header;
memset(&header, 0, sizeof(header));
header.version = _LINUX_CAPABILITY_VERSION_3;
__user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3];
if (capget(&header, &caps[0])) {
GTEST_LOG_(WARNING) << "failed to get process capabilities";
return false;
}
auto nice_idx = CAP_TO_INDEX(CAP_SYS_NICE);
auto nice_mask = CAP_TO_MASK(CAP_SYS_NICE);
return caps[nice_idx].effective & nice_mask;
}
long long medianSleepTime() {
std::vector<long long> sleepTimes;
constexpr size_t numSamples = 100;
for (size_t i = 0; i < numSamples; i++) {
auto start = std::chrono::steady_clock::now();
std::this_thread::sleep_for(std::chrono::nanoseconds(1));
auto end = std::chrono::steady_clock::now();
auto diff = end - start;
sleepTimes.push_back(diff.count());
}
constexpr auto median = numSamples / 2;
std::nth_element(sleepTimes.begin(), sleepTimes.begin() + median,
sleepTimes.end());
return sleepTimes[median];
}
static void AssertPolicy(SchedPolicy expected_policy) {
SchedPolicy current_policy;
ASSERT_EQ(0, get_sched_policy(0, ¤t_policy));
EXPECT_EQ(expected_policy, current_policy);
}
TEST(SchedPolicy, set_sched_policy) {
if (!schedboost_enabled()) {
// schedboost_enabled() (i.e. CONFIG_CGROUP_SCHEDTUNE) is optional;
// it's only needed on devices using energy-aware scheduler.
GTEST_LOG_(INFO) << "skipping test that requires CONFIG_CGROUP_SCHEDTUNE";
return;
}
ASSERT_EQ(0, set_sched_policy(0, SP_BACKGROUND));
ASSERT_EQ(0, set_cpuset_policy(0, SP_BACKGROUND));
AssertPolicy(SP_BACKGROUND);
ASSERT_EQ(0, set_sched_policy(0, SP_FOREGROUND));
ASSERT_EQ(0, set_cpuset_policy(0, SP_FOREGROUND));
AssertPolicy(SP_FOREGROUND);
}
TEST(SchedPolicy, set_sched_policy_timerslack) {
if (!hasCapSysNice()) {
GTEST_LOG_(INFO) << "skipping test that requires CAP_SYS_NICE";
return;
}
// A measureable effect of scheduling policy is that the kernel has 800x
// greater slack time in waking up a sleeping background thread.
//
// Look for 10x difference in how long FB and BG threads actually sleep
// when trying to sleep for 1 ns. This difference is large enough not
// to happen by chance, but small enough (compared to 800x) to keep inherent
// fuzziness in scheduler behavior from causing false negatives.
const unsigned int BG_FG_SLACK_FACTOR = 10;
ASSERT_EQ(0, set_sched_policy(0, SP_BACKGROUND));
auto bgSleepTime = medianSleepTime();
ASSERT_EQ(0, set_sched_policy(0, SP_FOREGROUND));
auto fgSleepTime = medianSleepTime();
ASSERT_GT(bgSleepTime, fgSleepTime * BG_FG_SLACK_FACTOR);
}
TEST(SchedPolicy, get_sched_policy_name) {
EXPECT_STREQ("bg", get_sched_policy_name(SP_BACKGROUND));
EXPECT_EQ(nullptr, get_sched_policy_name(SchedPolicy(-2)));
EXPECT_EQ(nullptr, get_sched_policy_name(SP_CNT));
}
TEST(SchedPolicy, get_cpuset_policy_profile_name) {
EXPECT_STREQ("CPUSET_SP_BACKGROUND", get_cpuset_policy_profile_name(SP_BACKGROUND));
EXPECT_EQ(nullptr, get_cpuset_policy_profile_name(SchedPolicy(-2)));
EXPECT_EQ(nullptr, get_cpuset_policy_profile_name(SP_CNT));
}
TEST(SchedPolicy, get_sched_policy_profile_name) {
EXPECT_STREQ("SCHED_SP_BACKGROUND", get_sched_policy_profile_name(SP_BACKGROUND));
EXPECT_EQ(nullptr, get_sched_policy_profile_name(SchedPolicy(-2)));
EXPECT_EQ(nullptr, get_sched_policy_profile_name(SP_CNT));
}
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