1 /*
2 * Copyright (C) 2020 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 "core_jni_helpers.h"
18
19 #include <cputimeinstate.h>
20
21 namespace android {
22
23 static constexpr uint64_t NSEC_PER_MSEC = 1000000;
24
copyVecsToArray(JNIEnv * env,std::vector<std::vector<uint64_t>> & vec)25 static jlongArray copyVecsToArray(JNIEnv *env, std::vector<std::vector<uint64_t>> &vec) {
26 jsize s = 0;
27 for (const auto &subVec : vec) s += subVec.size();
28 jlongArray ar = env->NewLongArray(s);
29 jsize start = 0;
30 for (auto &subVec : vec) {
31 for (uint32_t i = 0; i < subVec.size(); ++i) subVec[i] /= NSEC_PER_MSEC;
32 env->SetLongArrayRegion(ar, start, subVec.size(),
33 reinterpret_cast<const jlong*>(subVec.data()));
34 start += subVec.size();
35 }
36 return ar;
37 }
38
getUidCpuFreqTimeMs(JNIEnv * env,jclass,jint uid)39 static jlongArray getUidCpuFreqTimeMs(JNIEnv *env, jclass, jint uid) {
40 auto out = android::bpf::getUidCpuFreqTimes(uid);
41 if (!out) return env->NewLongArray(0);
42 return copyVecsToArray(env, out.value());
43 }
44
45 static const JNINativeMethod g_single_methods[] = {
46 {"readBpfData", "(I)[J", (void *)getUidCpuFreqTimeMs},
47 };
48
register_com_android_internal_os_KernelSingleUidTimeReader(JNIEnv * env)49 int register_com_android_internal_os_KernelSingleUidTimeReader(JNIEnv *env) {
50 return RegisterMethodsOrDie(env, "com/android/internal/os/KernelSingleUidTimeReader$Injector",
51 g_single_methods, NELEM(g_single_methods));
52 }
53
54 }
55