diff --git a/libs/cputimeinstate/cputimeinstate.cpp b/libs/cputimeinstate/cputimeinstate.cpp
new file mode 100644
index 0000000..4cddf94
--- /dev/null
+++ b/libs/cputimeinstate/cputimeinstate.cpp
@@ -0,0 +1,262 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#define LOG_TAG "libtimeinstate"
+
+#include "cputimeinstate.h"
+
+#include <dirent.h>
+#include <errno.h>
+#include <inttypes.h>
+
+#include <mutex>
+#include <set>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/parseint.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <bpf/BpfMap.h>
+#include <libbpf.h>
+#include <log/log.h>
+
+#define BPF_FS_PATH "/sys/fs/bpf/"
+
+using android::base::StringPrintf;
+using android::base::unique_fd;
+
+namespace android {
+namespace bpf {
+
+typedef struct {
+    uint32_t uid;
+    uint32_t freq;
+} time_key_t;
+
+typedef struct {
+    uint64_t ar[100];
+} val_t;
+
+static std::mutex gInitializedMutex;
+static bool gInitialized = false;
+static uint32_t gNPolicies = 0;
+static std::vector<std::vector<uint32_t>> gPolicyFreqs;
+static std::vector<std::vector<uint32_t>> gPolicyCpus;
+static std::set<uint32_t> gAllFreqs;
+static unique_fd gMapFd;
+
+static bool readNumbersFromFile(const std::string &path, std::vector<uint32_t> *out) {
+    std::string data;
+
+    if (!android::base::ReadFileToString(path, &data)) {
+        ALOGD("Failed to read file %s", path.c_str());
+        return false;
+    }
+
+    auto strings = android::base::Split(data, " \n");
+    for (const auto &s : strings) {
+        if (s.empty()) continue;
+        uint32_t n;
+        if (!android::base::ParseUint(s, &n)) {
+            ALOGD("Failed to parse file %s", path.c_str());
+            return false;
+        }
+        out->emplace_back(n);
+    }
+    return true;
+}
+
+static int isPolicyFile(const struct dirent *d) {
+    return android::base::StartsWith(d->d_name, "policy");
+}
+
+static int comparePolicyFiles(const struct dirent **d1, const struct dirent **d2) {
+    uint32_t policyN1, policyN2;
+    if (sscanf((*d1)->d_name, "policy%" SCNu32 "", &policyN1) != 1 ||
+        sscanf((*d2)->d_name, "policy%" SCNu32 "", &policyN2) != 1)
+        return 0;
+    return policyN1 - policyN2;
+}
+
+static bool initGlobals() {
+    std::lock_guard<std::mutex> guard(gInitializedMutex);
+    if (gInitialized) return true;
+
+    struct dirent **dirlist;
+    const char basepath[] = "/sys/devices/system/cpu/cpufreq";
+    int ret = scandir(basepath, &dirlist, isPolicyFile, comparePolicyFiles);
+    if (ret == -1) return false;
+    gNPolicies = ret;
+
+    std::vector<std::string> policyFileNames;
+    for (uint32_t i = 0; i < gNPolicies; ++i) {
+        policyFileNames.emplace_back(dirlist[i]->d_name);
+        free(dirlist[i]);
+    }
+    free(dirlist);
+
+    for (const auto &policy : policyFileNames) {
+        std::vector<uint32_t> freqs;
+        for (const auto &name : {"available", "boost"}) {
+            std::string path =
+                    StringPrintf("%s/%s/scaling_%s_frequencies", basepath, policy.c_str(), name);
+            if (!readNumbersFromFile(path, &freqs)) return false;
+        }
+        std::sort(freqs.begin(), freqs.end());
+        gPolicyFreqs.emplace_back(freqs);
+
+        for (auto freq : freqs) gAllFreqs.insert(freq);
+
+        std::vector<uint32_t> cpus;
+        std::string path = StringPrintf("%s/%s/%s", basepath, policy.c_str(), "related_cpus");
+        if (!readNumbersFromFile(path, &cpus)) return false;
+        gPolicyCpus.emplace_back(cpus);
+    }
+
+    gMapFd = unique_fd{bpf_obj_get(BPF_FS_PATH "map_time_in_state_uid_times")};
+    if (gMapFd < 0) return false;
+
+    gInitialized = true;
+    return true;
+}
+
+static bool attachTracepointProgram(const std::string &eventType, const std::string &eventName) {
+    std::string path = StringPrintf(BPF_FS_PATH "prog_time_in_state_tracepoint_%s_%s",
+                                    eventType.c_str(), eventName.c_str());
+    int prog_fd = bpf_obj_get(path.c_str());
+    if (prog_fd < 0) {
+        ALOGD("bpf_obj_get() failed for program %s", path.c_str());
+        return false;
+    }
+    if (bpf_attach_tracepoint(prog_fd, eventType.c_str(), eventName.c_str()) < 0) {
+        ALOGD("Failed to attach bpf program to tracepoint %s/%s", eventType.c_str(),
+              eventName.c_str());
+        return false;
+    }
+    return true;
+}
+
+// Start tracking and aggregating data to be reported by getUidCpuFreqTimes and getUidsCpuFreqTimes.
+// Returns true on success, false otherwise.
+// Tracking is active only once a live process has successfully called this function; if the calling
+// process dies then it must be called again to resume tracking.
+// This function should *not* be called while tracking is already active; doing so is unnecessary
+// and can lead to accounting errors.
+bool startTrackingUidCpuFreqTimes() {
+    return attachTracepointProgram("sched", "sched_switch") &&
+            attachTracepointProgram("power", "cpu_frequency");
+}
+
+// Retrieve the times in ns that uid spent running at each CPU frequency and store in freqTimes.
+// Returns false on error. Otherwise, returns true and populates freqTimes with a vector of vectors
+// using the format:
+// [[t0_0, t0_1, ...],
+//  [t1_0, t1_1, ...], ...]
+// where ti_j is the ns that uid spent running on the ith cluster at that cluster's jth lowest freq.
+bool getUidCpuFreqTimes(uint32_t uid, std::vector<std::vector<uint64_t>> *freqTimes) {
+    if (!gInitialized && !initGlobals()) return false;
+    time_key_t key = {.uid = uid, .freq = 0};
+
+    freqTimes->clear();
+    freqTimes->resize(gNPolicies);
+    std::vector<uint32_t> idxs(gNPolicies, 0);
+
+    val_t value;
+    for (uint32_t freq : gAllFreqs) {
+        key.freq = freq;
+        int ret = findMapEntry(gMapFd, &key, &value);
+        if (ret) {
+            if (errno == ENOENT)
+                memset(&value.ar, 0, sizeof(value.ar));
+            else
+                return false;
+        }
+        for (uint32_t i = 0; i < gNPolicies; ++i) {
+            if (idxs[i] == gPolicyFreqs[i].size() || freq != gPolicyFreqs[i][idxs[i]]) continue;
+            uint64_t time = 0;
+            for (uint32_t cpu : gPolicyCpus[i]) time += value.ar[cpu];
+            idxs[i] += 1;
+            (*freqTimes)[i].emplace_back(time);
+        }
+    }
+
+    return true;
+}
+
+// Retrieve the times in ns that each uid spent running at each CPU freq and store in freqTimeMap.
+// Returns false on error. Otherwise, returns true and populates freqTimeMap with a map from uids to
+// vectors of vectors using the format:
+// { uid0 -> [[t0_0_0, t0_0_1, ...], [t0_1_0, t0_1_1, ...], ...],
+//   uid1 -> [[t1_0_0, t1_0_1, ...], [t1_1_0, t1_1_1, ...], ...], ... }
+// where ti_j_k is the ns uid i spent running on the jth cluster at the cluster's kth lowest freq.
+bool getUidsCpuFreqTimes(
+        std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>> *freqTimeMap) {
+    if (!gInitialized && !initGlobals()) return false;
+
+    int fd = bpf_obj_get(BPF_FS_PATH "map_time_in_state_uid_times");
+    if (fd < 0) return false;
+    BpfMap<time_key_t, val_t> m(fd);
+
+    std::vector<std::unordered_map<uint32_t, uint32_t>> policyFreqIdxs;
+    for (uint32_t i = 0; i < gNPolicies; ++i) {
+        std::unordered_map<uint32_t, uint32_t> freqIdxs;
+        for (size_t j = 0; j < gPolicyFreqs[i].size(); ++j) freqIdxs[gPolicyFreqs[i][j]] = j;
+        policyFreqIdxs.emplace_back(freqIdxs);
+    }
+
+    auto fn = [freqTimeMap, &policyFreqIdxs](const time_key_t &key, const val_t &val,
+                                             const BpfMap<time_key_t, val_t> &) {
+        if (freqTimeMap->find(key.uid) == freqTimeMap->end()) {
+            std::vector<std::vector<uint64_t>> v;
+            for (uint32_t i = 0; i < gNPolicies; ++i) {
+                std::vector<uint64_t> v2(gPolicyFreqs[i].size(), 0);
+                v.emplace_back(v2);
+            }
+            (*freqTimeMap)[key.uid] = v;
+        }
+
+        for (size_t policy = 0; policy < gNPolicies; ++policy) {
+            for (const auto &cpu : gPolicyCpus[policy]) {
+                uint32_t cpuTime = val.ar[cpu];
+                if (cpuTime == 0) continue;
+                auto freqIdx = policyFreqIdxs[policy][key.freq];
+                (*freqTimeMap)[key.uid][policy][freqIdx] += cpuTime;
+            }
+        }
+        return android::netdutils::status::ok;
+    };
+    return isOk(m.iterateWithValue(fn));
+}
+
+// Clear all time in state data for a given uid. Returns false on error, true otherwise.
+bool clearUidCpuFreqTimes(uint32_t uid) {
+    if (!gInitialized && !initGlobals()) return false;
+    time_key_t key = {.uid = uid, .freq = 0};
+
+    std::vector<uint32_t> idxs(gNPolicies, 0);
+    for (auto freq : gAllFreqs) {
+        key.freq = freq;
+        if (deleteMapEntry(gMapFd, &key) && errno != ENOENT) return false;
+    }
+    return true;
+}
+
+} // namespace bpf
+} // namespace android