Merge "libtimeinstate: add functions to read only recently-updated stats"

3 files changed, 236 insertions, 79 deletions

diff --git a/libs/cputimeinstate/cputimeinstate.cpp b/libs/cputimeinstate/cputimeinstate.cpp
index 1465296bac..05a462e026 100644
--- a/libs/cputimeinstate/cputimeinstate.cpp
+++ b/libs/cputimeinstate/cputimeinstate.cpp
@@ -58,6 +58,7 @@ static std::vector<std::vector<uint32_t>> gPolicyCpus;
 static std::set<uint32_t> gAllFreqs;
 static unique_fd gTisMapFd;
 static unique_fd gConcurrentMapFd;
+static unique_fd gUidLastUpdateMapFd;
 
 static std::optional<std::vector<uint32_t>> readNumbersFromFile(const std::string &path) {
     std::string data;
@@ -144,6 +145,10 @@ static bool initGlobals() {
             unique_fd{bpf_obj_get(BPF_FS_PATH "map_time_in_state_uid_concurrent_times_map")};
     if (gConcurrentMapFd < 0) return false;
 
+    gUidLastUpdateMapFd =
+            unique_fd{bpf_obj_get(BPF_FS_PATH "map_time_in_state_uid_last_update_map")};
+    if (gUidLastUpdateMapFd < 0) return false;
+
     gInitialized = true;
     return true;
 }
@@ -263,6 +268,18 @@ std::optional<std::vector<std::vector<uint64_t>>> getUidCpuFreqTimes(uint32_t ui
     return out;
 }
 
+static std::optional<bool> uidUpdatedSince(uint32_t uid, uint64_t lastUpdate,
+                                           uint64_t *newLastUpdate) {
+    uint64_t uidLastUpdate;
+    if (findMapEntry(gUidLastUpdateMapFd, &uid, &uidLastUpdate)) return {};
+    // Updates that occurred during the previous read may have been missed. To mitigate
+    // this, don't ignore entries updated up to 1s before *lastUpdate
+    constexpr uint64_t NSEC_PER_SEC = 1000000000;
+    if (uidLastUpdate + NSEC_PER_SEC < lastUpdate) return false;
+    if (uidLastUpdate > *newLastUpdate) *newLastUpdate = uidLastUpdate;
+    return true;
+}
+
 // Retrieve the times in ns that each uid spent running at each CPU freq.
 // Return contains no value on error, otherwise it contains a map from uids to vectors of vectors
 // using the format:
@@ -271,6 +288,14 @@ std::optional<std::vector<std::vector<uint64_t>>> getUidCpuFreqTimes(uint32_t ui
 // where ti_j_k is the ns uid i spent running on the jth cluster at the cluster's kth lowest freq.
 std::optional<std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>>>
 getUidsCpuFreqTimes() {
+    return getUidsUpdatedCpuFreqTimes(nullptr);
+}
+
+// Retrieve the times in ns that each uid spent running at each CPU freq, excluding UIDs that have
+// not run since before lastUpdate.
+// Return format is the same as getUidsCpuFreqTimes()
+std::optional<std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>>>
+getUidsUpdatedCpuFreqTimes(uint64_t *lastUpdate) {
     if (!gInitialized && !initGlobals()) return {};
     time_key_t key, prevKey;
     std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>> map;
@@ -282,8 +307,14 @@ getUidsCpuFreqTimes() {
     std::vector<std::vector<uint64_t>> mapFormat;
     for (const auto &freqList : gPolicyFreqs) mapFormat.emplace_back(freqList.size(), 0);
 
+    uint64_t newLastUpdate = lastUpdate ? *lastUpdate : 0;
     std::vector<tis_val_t> vals(gNCpus);
     do {
+        if (lastUpdate) {
+            auto uidUpdated = uidUpdatedSince(key.uid, *lastUpdate, &newLastUpdate);
+            if (!uidUpdated.has_value()) return {};
+            if (!*uidUpdated) continue;
+        }
         if (findMapEntry(gTisMapFd, &key, vals.data())) return {};
         if (map.find(key.uid) == map.end()) map.emplace(key.uid, mapFormat);
 
@@ -299,8 +330,9 @@ getUidsCpuFreqTimes() {
             }
         }
         prevKey = key;
-    } while (!getNextMapKey(gTisMapFd, &prevKey, &key));
+    } while (prevKey = key, !getNextMapKey(gTisMapFd, &prevKey, &key));
     if (errno != ENOENT) return {};
+    if (lastUpdate && newLastUpdate > *lastUpdate) *lastUpdate = newLastUpdate;
     return map;
 }
 
@@ -365,6 +397,15 @@ std::optional<concurrent_time_t> getUidConcurrentTimes(uint32_t uid, bool retry)
 // where ai is the ns spent running concurrently with tasks on i other cpus and pi_j is the ns spent
 // running on the ith cluster, concurrently with tasks on j other cpus in the same cluster.
 std::optional<std::unordered_map<uint32_t, concurrent_time_t>> getUidsConcurrentTimes() {
+    return getUidsUpdatedConcurrentTimes(nullptr);
+}
+
+// Retrieve the times in ns that each uid spent running concurrently with each possible number of
+// other tasks on each cluster (policy times) and overall (active times), excluding UIDs that have
+// not run since before lastUpdate.
+// Return format is the same as getUidsConcurrentTimes()
+std::optional<std::unordered_map<uint32_t, concurrent_time_t>> getUidsUpdatedConcurrentTimes(
+        uint64_t *lastUpdate) {
     if (!gInitialized && !initGlobals()) return {};
     time_key_t key, prevKey;
     std::unordered_map<uint32_t, concurrent_time_t> ret;
@@ -379,7 +420,13 @@ std::optional<std::unordered_map<uint32_t, concurrent_time_t>> getUidsConcurrent
     std::vector<concurrent_val_t> vals(gNCpus);
     std::vector<uint64_t>::iterator activeBegin, activeEnd, policyBegin, policyEnd;
 
+    uint64_t newLastUpdate = lastUpdate ? *lastUpdate : 0;
     do {
+        if (lastUpdate) {
+            auto uidUpdated = uidUpdatedSince(key.uid, *lastUpdate, &newLastUpdate);
+            if (!uidUpdated.has_value()) return {};
+            if (!*uidUpdated) continue;
+        }
         if (findMapEntry(gConcurrentMapFd, &key, vals.data())) return {};
         if (ret.find(key.uid) == ret.end()) ret.emplace(key.uid, retFormat);
 
@@ -405,8 +452,7 @@ std::optional<std::unordered_map<uint32_t, concurrent_time_t>> getUidsConcurrent
                                std::plus<uint64_t>());
             }
         }
-        prevKey = key;
-    } while (!getNextMapKey(gConcurrentMapFd, &prevKey, &key));
+    } while (prevKey = key, !getNextMapKey(gConcurrentMapFd, &prevKey, &key));
     if (errno != ENOENT) return {};
     for (const auto &[key, value] : ret) {
         if (!verifyConcurrentTimes(value)) {
@@ -414,6 +460,7 @@ std::optional<std::unordered_map<uint32_t, concurrent_time_t>> getUidsConcurrent
             if (val.has_value()) ret[key] = val.value();
         }
     }
+    if (lastUpdate && newLastUpdate > *lastUpdate) *lastUpdate = newLastUpdate;
     return ret;
 }
 
@@ -446,6 +493,8 @@ bool clearUidTimes(uint32_t uid) {
             return false;
         if (deleteMapEntry(gConcurrentMapFd, &key) && errno != ENOENT) return false;
     }
+
+    if (deleteMapEntry(gUidLastUpdateMapFd, &uid) && errno != ENOENT) return false;
     return true;
 }
 
diff --git a/libs/cputimeinstate/cputimeinstate.h b/libs/cputimeinstate/cputimeinstate.h
index 49469d8e04..b7600f59e0 100644
--- a/libs/cputimeinstate/cputimeinstate.h
+++ b/libs/cputimeinstate/cputimeinstate.h
@@ -26,6 +26,8 @@ bool startTrackingUidTimes();
 std::optional<std::vector<std::vector<uint64_t>>> getUidCpuFreqTimes(uint32_t uid);
 std::optional<std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>>>
     getUidsCpuFreqTimes();
+std::optional<std::unordered_map<uint32_t, std::vector<std::vector<uint64_t>>>>
+    getUidsUpdatedCpuFreqTimes(uint64_t *lastUpdate);
 std::optional<std::vector<std::vector<uint32_t>>> getCpuFreqs();
 
 struct concurrent_time_t {
@@ -35,6 +37,8 @@ struct concurrent_time_t {
 
 std::optional<concurrent_time_t> getUidConcurrentTimes(uint32_t uid, bool retry = true);
 std::optional<std::unordered_map<uint32_t, concurrent_time_t>> getUidsConcurrentTimes();
+std::optional<std::unordered_map<uint32_t, concurrent_time_t>>
+    getUidsUpdatedConcurrentTimes(uint64_t *lastUpdate);
 bool clearUidTimes(unsigned int uid);
 
 } // namespace bpf
diff --git a/libs/cputimeinstate/testtimeinstate.cpp b/libs/cputimeinstate/testtimeinstate.cpp
index 23d87fd646..ea2a2008b7 100644
--- a/libs/cputimeinstate/testtimeinstate.cpp
+++ b/libs/cputimeinstate/testtimeinstate.cpp
@@ -115,71 +115,169 @@ TEST(TimeInStateTest, SingleUidTimesConsistent) {
 }
 
 TEST(TimeInStateTest, AllUidTimeInState) {
-    vector<size_t> sizes;
-    auto map = getUidsCpuFreqTimes();
-    ASSERT_TRUE(map.has_value());
+    uint64_t zero = 0;
+    auto maps = {getUidsCpuFreqTimes(), getUidsUpdatedCpuFreqTimes(&zero)};
+    for (const auto &map : maps) {
+        ASSERT_TRUE(map.has_value());
 
-    ASSERT_FALSE(map->empty());
+        ASSERT_FALSE(map->empty());
 
-    auto firstEntry = map->begin()->second;
-    for (const auto &subEntry : firstEntry) sizes.emplace_back(subEntry.size());
+        vector<size_t> sizes;
+        auto firstEntry = map->begin()->second;
+        for (const auto &subEntry : firstEntry) sizes.emplace_back(subEntry.size());
 
-    for (const auto &vec : *map) {
-        ASSERT_EQ(vec.second.size(), sizes.size());
-        for (size_t i = 0; i < vec.second.size(); ++i) ASSERT_EQ(vec.second[i].size(), sizes[i]);
+        for (const auto &vec : *map) {
+            ASSERT_EQ(vec.second.size(), sizes.size());
+            for (size_t i = 0; i < vec.second.size(); ++i) ASSERT_EQ(vec.second[i].size(), sizes[i]);
+        }
     }
 }
 
-TEST(TimeInStateTest, SingleAndAllUidTimeInStateConsistent) {
-    auto map = getUidsCpuFreqTimes();
-    ASSERT_TRUE(map.has_value());
-    ASSERT_FALSE(map->empty());
+void TestCheckUpdate(const std::vector<std::vector<uint64_t>> &before,
+                     const std::vector<std::vector<uint64_t>> &after) {
+    ASSERT_EQ(before.size(), after.size());
+    uint64_t sumBefore = 0, sumAfter = 0;
+    for (size_t i = 0; i < before.size(); ++i) {
+        ASSERT_EQ(before[i].size(), after[i].size());
+        for (size_t j = 0; j < before[i].size(); ++j) {
+            // Times should never decrease
+            ASSERT_LE(before[i][j], after[i][j]);
+        }
+        sumBefore += std::accumulate(before[i].begin(), before[i].end(), (uint64_t)0);
+        sumAfter += std::accumulate(after[i].begin(), after[i].end(), (uint64_t)0);
+    }
+    ASSERT_LE(sumBefore, sumAfter);
+    ASSERT_LE(sumAfter - sumBefore, NSEC_PER_SEC);
+}
 
-    for (const auto &kv : *map) {
-        uint32_t uid = kv.first;
-        auto times1 = kv.second;
-        auto times2 = getUidCpuFreqTimes(uid);
-        ASSERT_TRUE(times2.has_value());
-
-        ASSERT_EQ(times1.size(), times2->size());
-        for (uint32_t i = 0; i < times1.size(); ++i) {
-            ASSERT_EQ(times1[i].size(), (*times2)[i].size());
-            for (uint32_t j = 0; j < times1[i].size(); ++j) {
-                ASSERT_LE((*times2)[i][j] - times1[i][j], NSEC_PER_SEC);
+TEST(TimeInStateTest, AllUidUpdatedTimeInState) {
+    uint64_t lastUpdate = 0;
+    auto map1 = getUidsUpdatedCpuFreqTimes(&lastUpdate);
+    ASSERT_TRUE(map1.has_value());
+    ASSERT_FALSE(map1->empty());
+    ASSERT_NE(lastUpdate, (uint64_t)0);
+    uint64_t oldLastUpdate = lastUpdate;
+
+    // Sleep briefly to trigger a context switch, ensuring we see at least one update.
+    struct timespec ts;
+    ts.tv_sec = 0;
+    ts.tv_nsec = 1000000;
+    nanosleep (&ts, NULL);
+
+    auto map2 = getUidsUpdatedCpuFreqTimes(&lastUpdate);
+    ASSERT_TRUE(map2.has_value());
+    ASSERT_FALSE(map2->empty());
+    ASSERT_NE(lastUpdate, oldLastUpdate);
+
+    bool someUidsExcluded = false;
+    for (const auto &[uid, v] : *map1) {
+        if (map2->find(uid) == map2->end()) {
+            someUidsExcluded = true;
+            break;
+        }
+    }
+    ASSERT_TRUE(someUidsExcluded);
+
+    for (const auto &[uid, newTimes] : *map2) {
+        ASSERT_NE(map1->find(uid), map1->end());
+        ASSERT_NO_FATAL_FAILURE(TestCheckUpdate((*map1)[uid], newTimes));
+    }
+}
+
+TEST(TimeInStateTest, SingleAndAllUidTimeInStateConsistent) {
+    uint64_t zero = 0;
+    auto maps = {getUidsCpuFreqTimes(), getUidsUpdatedCpuFreqTimes(&zero)};
+    for (const auto &map : maps) {
+        ASSERT_TRUE(map.has_value());
+        ASSERT_FALSE(map->empty());
+
+        for (const auto &kv : *map) {
+            uint32_t uid = kv.first;
+            auto times1 = kv.second;
+            auto times2 = getUidCpuFreqTimes(uid);
+            ASSERT_TRUE(times2.has_value());
+
+            ASSERT_EQ(times1.size(), times2->size());
+            for (uint32_t i = 0; i < times1.size(); ++i) {
+                ASSERT_EQ(times1[i].size(), (*times2)[i].size());
+                for (uint32_t j = 0; j < times1[i].size(); ++j) {
+                    ASSERT_LE((*times2)[i][j] - times1[i][j], NSEC_PER_SEC);
+                }
             }
         }
     }
 }
 
 TEST(TimeInStateTest, AllUidConcurrentTimes) {
-    auto map = getUidsConcurrentTimes();
-    ASSERT_TRUE(map.has_value());
-    ASSERT_FALSE(map->empty());
-
-    auto firstEntry = map->begin()->second;
-    for (const auto &kv : *map) {
-        ASSERT_EQ(kv.second.active.size(), firstEntry.active.size());
-        ASSERT_EQ(kv.second.policy.size(), firstEntry.policy.size());
-        for (size_t i = 0; i < kv.second.policy.size(); ++i) {
-            ASSERT_EQ(kv.second.policy[i].size(), firstEntry.policy[i].size());
+    uint64_t zero = 0;
+    auto maps = {getUidsConcurrentTimes(), getUidsUpdatedConcurrentTimes(&zero)};
+    for (const auto &map : maps) {
+        ASSERT_TRUE(map.has_value());
+        ASSERT_FALSE(map->empty());
+
+        auto firstEntry = map->begin()->second;
+        for (const auto &kv : *map) {
+            ASSERT_EQ(kv.second.active.size(), firstEntry.active.size());
+            ASSERT_EQ(kv.second.policy.size(), firstEntry.policy.size());
+            for (size_t i = 0; i < kv.second.policy.size(); ++i) {
+                ASSERT_EQ(kv.second.policy[i].size(), firstEntry.policy[i].size());
+            }
         }
     }
 }
 
-TEST(TimeInStateTest, SingleAndAllUidConcurrentTimesConsistent) {
-    auto map = getUidsConcurrentTimes();
-    ASSERT_TRUE(map.has_value());
-    for (const auto &kv : *map) {
-        uint32_t uid = kv.first;
-        auto times1 = kv.second;
-        auto times2 = getUidConcurrentTimes(uid);
-        ASSERT_TRUE(times2.has_value());
-        for (uint32_t i = 0; i < times1.active.size(); ++i) {
-            ASSERT_LE(times2->active[i] - times1.active[i], NSEC_PER_SEC);
+TEST(TimeInStateTest, AllUidUpdatedConcurrentTimes) {
+    uint64_t lastUpdate = 0;
+    auto map1 = getUidsUpdatedConcurrentTimes(&lastUpdate);
+    ASSERT_TRUE(map1.has_value());
+    ASSERT_FALSE(map1->empty());
+    ASSERT_NE(lastUpdate, (uint64_t)0);
+
+    // Sleep briefly to trigger a context switch, ensuring we see at least one update.
+    struct timespec ts;
+    ts.tv_sec = 0;
+    ts.tv_nsec = 1000000;
+    nanosleep (&ts, NULL);
+
+    uint64_t oldLastUpdate = lastUpdate;
+    auto map2 = getUidsUpdatedConcurrentTimes(&lastUpdate);
+    ASSERT_TRUE(map2.has_value());
+    ASSERT_FALSE(map2->empty());
+    ASSERT_NE(lastUpdate, oldLastUpdate);
+
+    bool someUidsExcluded = false;
+    for (const auto &[uid, v] : *map1) {
+        if (map2->find(uid) == map2->end()) {
+            someUidsExcluded = true;
+            break;
         }
-        for (uint32_t i = 0; i < times1.policy.size(); ++i) {
-            for (uint32_t j = 0; j < times1.policy[i].size(); ++j) {
-                ASSERT_LE(times2->policy[i][j] - times1.policy[i][j], NSEC_PER_SEC);
+    }
+    ASSERT_TRUE(someUidsExcluded);
+
+    for (const auto &[uid, newTimes] : *map2) {
+        ASSERT_NE(map1->find(uid), map1->end());
+        ASSERT_NO_FATAL_FAILURE(TestCheckUpdate({(*map1)[uid].active},{newTimes.active}));
+        ASSERT_NO_FATAL_FAILURE(TestCheckUpdate((*map1)[uid].policy, newTimes.policy));
+    }
+}
+
+TEST(TimeInStateTest, SingleAndAllUidConcurrentTimesConsistent) {
+    uint64_t zero = 0;
+    auto maps = {getUidsConcurrentTimes(), getUidsUpdatedConcurrentTimes(&zero)};
+    for (const auto &map : maps) {
+        ASSERT_TRUE(map.has_value());
+        for (const auto &kv : *map) {
+            uint32_t uid = kv.first;
+            auto times1 = kv.second;
+            auto times2 = getUidConcurrentTimes(uid);
+            ASSERT_TRUE(times2.has_value());
+            for (uint32_t i = 0; i < times1.active.size(); ++i) {
+                ASSERT_LE(times2->active[i] - times1.active[i], NSEC_PER_SEC);
+            }
+            for (uint32_t i = 0; i < times1.policy.size(); ++i) {
+                for (uint32_t j = 0; j < times1.policy[i].size(); ++j) {
+                    ASSERT_LE(times2->policy[i][j] - times1.policy[i][j], NSEC_PER_SEC);
+                }
             }
         }
     }
@@ -242,45 +340,51 @@ TEST(TimeInStateTest, AllUidConcurrentTimesMonotonic) {
 }
 
 TEST(TimeInStateTest, AllUidTimeInStateSanityCheck) {
-    auto map = getUidsCpuFreqTimes();
-    ASSERT_TRUE(map.has_value());
-
-    bool foundLargeValue = false;
-    for (const auto &kv : *map) {
-        for (const auto &timeVec : kv.second) {
-            for (const auto &time : timeVec) {
-                ASSERT_LE(time, NSEC_PER_YEAR);
-                if (time > UINT32_MAX) foundLargeValue = true;
+    uint64_t zero = 0;
+    auto maps = {getUidsCpuFreqTimes(), getUidsUpdatedCpuFreqTimes(&zero)};
+    for (const auto &map : maps) {
+        ASSERT_TRUE(map.has_value());
+
+        bool foundLargeValue = false;
+        for (const auto &kv : *map) {
+            for (const auto &timeVec : kv.second) {
+                for (const auto &time : timeVec) {
+                    ASSERT_LE(time, NSEC_PER_YEAR);
+                    if (time > UINT32_MAX) foundLargeValue = true;
+                }
             }
         }
+        // UINT32_MAX nanoseconds is less than 5 seconds, so if every part of our pipeline is using
+        // uint64_t as expected, we should have some times higher than that.
+        ASSERT_TRUE(foundLargeValue);
     }
-    // UINT32_MAX nanoseconds is less than 5 seconds, so if every part of our pipeline is using
-    // uint64_t as expected, we should have some times higher than that.
-    ASSERT_TRUE(foundLargeValue);
 }
 
 TEST(TimeInStateTest, AllUidConcurrentTimesSanityCheck) {
-    auto concurrentMap = getUidsConcurrentTimes();
-    ASSERT_TRUE(concurrentMap);
-
-    bool activeFoundLargeValue = false;
-    bool policyFoundLargeValue = false;
-    for (const auto &kv : *concurrentMap) {
-        for (const auto &time : kv.second.active) {
-            ASSERT_LE(time, NSEC_PER_YEAR);
-            if (time > UINT32_MAX) activeFoundLargeValue = true;
-        }
-        for (const auto &policyTimeVec : kv.second.policy) {
-            for (const auto &time : policyTimeVec) {
+    uint64_t zero = 0;
+    auto maps = {getUidsConcurrentTimes(), getUidsUpdatedConcurrentTimes(&zero)};
+    for (const auto &concurrentMap : maps) {
+        ASSERT_TRUE(concurrentMap);
+
+        bool activeFoundLargeValue = false;
+        bool policyFoundLargeValue = false;
+        for (const auto &kv : *concurrentMap) {
+            for (const auto &time : kv.second.active) {
                 ASSERT_LE(time, NSEC_PER_YEAR);
-                if (time > UINT32_MAX) policyFoundLargeValue = true;
+                if (time > UINT32_MAX) activeFoundLargeValue = true;
+            }
+            for (const auto &policyTimeVec : kv.second.policy) {
+                for (const auto &time : policyTimeVec) {
+                    ASSERT_LE(time, NSEC_PER_YEAR);
+                    if (time > UINT32_MAX) policyFoundLargeValue = true;
+                }
             }
         }
+        // UINT32_MAX nanoseconds is less than 5 seconds, so if every part of our pipeline is using
+        // uint64_t as expected, we should have some times higher than that.
+        ASSERT_TRUE(activeFoundLargeValue);
+        ASSERT_TRUE(policyFoundLargeValue);
     }
-    // UINT32_MAX nanoseconds is less than 5 seconds, so if every part of our pipeline is using
-    // uint64_t as expected, we should have some times higher than that.
-    ASSERT_TRUE(activeFoundLargeValue);
-    ASSERT_TRUE(policyFoundLargeValue);
 }
 
 TEST(TimeInStateTest, AllUidTimesConsistent) {