libtimeinstate: use std::optional
Simplify the interface and implementation of libtimeinstate by using
std::optional instead of output parameters.
Test: libtimeinstate_test passes
Bug: 78498733
Change-Id: I97b697c9b51c31245b3c141eff063eba865f5d73
Signed-off-by: Connor O'Brien <connoro@google.com>
(cherry picked from commit 4b9c498812c5f3635c941483a6fec19cb432bcb8)
Merged-In: I97b697c9b51c31245b3c141eff063eba865f5d73
diff --git a/libs/cputimeinstate/cputimeinstate.cpp b/libs/cputimeinstate/cputimeinstate.cpp
index 4ba66a5..41cbde1 100644
--- a/libs/cputimeinstate/cputimeinstate.cpp
+++ b/libs/cputimeinstate/cputimeinstate.cpp
@@ -23,6 +23,7 @@
#include <inttypes.h>
#include <mutex>
+#include <optional>
#include <set>
#include <string>
#include <unordered_map>
@@ -62,19 +63,20 @@
static std::set<uint32_t> gAllFreqs;
static unique_fd gMapFd;
-static bool readNumbersFromFile(const std::string &path, std::vector<uint32_t> *out) {
+static std::optional<std::vector<uint32_t>> readNumbersFromFile(const std::string &path) {
std::string data;
- if (!android::base::ReadFileToString(path, &data)) return false;
+ if (!android::base::ReadFileToString(path, &data)) return {};
auto strings = android::base::Split(data, " \n");
+ std::vector<uint32_t> ret;
for (const auto &s : strings) {
if (s.empty()) continue;
uint32_t n;
- if (!android::base::ParseUint(s, &n)) return false;
- out->emplace_back(n);
+ if (!android::base::ParseUint(s, &n)) return {};
+ ret.emplace_back(n);
}
- return true;
+ return ret;
}
static int isPolicyFile(const struct dirent *d) {
@@ -111,17 +113,19 @@
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;
+ auto nums = readNumbersFromFile(path);
+ if (!nums) return false;
+ freqs.insert(freqs.end(), nums->begin(), nums->end());
}
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);
+ auto cpus = readNumbersFromFile(path);
+ if (!cpus) return false;
+ gPolicyCpus.emplace_back(*cpus);
}
gMapFd = unique_fd{bpf_obj_get(BPF_FS_PATH "map_time_in_state_uid_times_map")};
@@ -151,17 +155,15 @@
}
// 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:
+// Return contains no value on error, otherwise it contains 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;
+std::optional<std::vector<std::vector<uint64_t>>> getUidCpuFreqTimes(uint32_t uid) {
+ if (!gInitialized && !initGlobals()) return {};
time_key_t key = {.uid = uid, .freq = 0};
- freqTimes->clear();
- freqTimes->resize(gNPolicies);
+ std::vector<std::vector<uint64_t>> out(gNPolicies);
std::vector<uint32_t> idxs(gNPolicies, 0);
val_t value;
@@ -172,32 +174,32 @@
if (errno == ENOENT)
memset(&value.ar, 0, sizeof(value.ar));
else
- return false;
+ return {};
}
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);
+ out[i].emplace_back(time);
}
}
- return true;
+ return out;
}
// 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:
+// Return contains no value on error, otherwise it contains 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;
+std::optional<std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>>>
+getUidsCpuFreqTimes() {
+ if (!gInitialized && !initGlobals()) return {};
int fd = bpf_obj_get(BPF_FS_PATH "map_time_in_state_uid_times_map");
- if (fd < 0) return false;
+ if (fd < 0) return {};
BpfMap<time_key_t, val_t> m(fd);
std::vector<std::unordered_map<uint32_t, uint32_t>> policyFreqIdxs;
@@ -206,25 +208,26 @@
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,
+ std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>> map;
+ auto fn = [&map, &policyFreqIdxs](const time_key_t &key, const val_t &val,
const BpfMap<time_key_t, val_t> &) {
- if (freqTimeMap->find(key.uid) == freqTimeMap->end()) {
- (*freqTimeMap)[key.uid].resize(gNPolicies);
+ if (map.find(key.uid) == map.end()) {
+ map[key.uid].resize(gNPolicies);
for (uint32_t i = 0; i < gNPolicies; ++i) {
- (*freqTimeMap)[key.uid][i].resize(gPolicyFreqs[i].size(), 0);
+ map[key.uid][i].resize(gPolicyFreqs[i].size(), 0);
}
}
for (size_t policy = 0; policy < gNPolicies; ++policy) {
for (const auto &cpu : gPolicyCpus[policy]) {
auto freqIdx = policyFreqIdxs[policy][key.freq];
- (*freqTimeMap)[key.uid][policy][freqIdx] += val.ar[cpu];
+ map[key.uid][policy][freqIdx] += val.ar[cpu];
}
}
return android::netdutils::status::ok;
};
- return isOk(m.iterateWithValue(fn));
+ if (isOk(m.iterateWithValue(fn))) return map;
+ return {};
}
// Clear all time in state data for a given uid. Returns false on error, true otherwise.