commit 8a8d16ceea1e5b7a2f8c41e17b5d993035f50f5d
author Yao Chen <yaochen@google.com> Thu Feb 08 14:50:40 2018 -0800
committer Yao Chen <yaochen@google.com> Mon Feb 12 10:38:45 2018 -0800
tree f3c3ba9f29eebe1c22d79cd49516306093925e21
parent 4f07fa4e748c4f259a7ae9c06f89e44a9c69acff

Statsd CPU optimization.

The key change is to revamp how we parse/store/match a log event, especially how we match repeated
field and attribution nodes, and how we construct dimensions and compare them.

+ We use a integer to encode the field of a log element. And also encode the FieldMatcher into an
integer and a bit mask. The log matching becomes 2 integer operations.

+ Dimension is stored as encoded field and value pair. Checking if 2 dimensions are equal is then
  becoming checking if the underlying integers are equal. The integers are stored contiguously
  in memory, so it's much faster than previous tree structure.

Start review from FieldValue.h

Test: statsd_test + new unit tests

Bug: 72659059

Change-Id: Iec8daeacdd3f39ab297c10ab9cd7b710a9c42e86

cmds/statsd/src/condition/SimpleConditionTracker.h

diff --git a/cmds/statsd/src/condition/SimpleConditionTracker.h b/cmds/statsd/src/condition/SimpleConditionTracker.h
index ce9a02d..c565129 100644
--- a/cmds/statsd/src/condition/SimpleConditionTracker.h
+++ b/cmds/statsd/src/condition/SimpleConditionTracker.h
@@ -48,14 +48,14 @@
 
     void isConditionMet(const ConditionKey& conditionParameters,
                         const std::vector<sp<ConditionTracker>>& allConditions,
-                        const FieldMatcher& dimensionFields,
+                        const vector<Matcher>& dimensionFields,
                         std::vector<ConditionState>& conditionCache,
-                        std::unordered_set<HashableDimensionKey> &dimensionsKeySet) const override;
+                        std::unordered_set<HashableDimensionKey>& dimensionsKeySet) const override;
 
     ConditionState getMetConditionDimension(
             const std::vector<sp<ConditionTracker>>& allConditions,
-            const FieldMatcher& dimensionFields,
-            std::unordered_set<HashableDimensionKey> &dimensionsKeySet) const override;
+            const vector<Matcher>& dimensionFields,
+            std::unordered_set<HashableDimensionKey>& dimensionsKeySet) const override;
 
 private:
     const ConfigKey mConfigKey;
@@ -73,17 +73,17 @@
 
     ConditionState mInitialValue;
 
-    FieldMatcher mOutputDimensions;
+    std::vector<Matcher> mOutputDimensions;
+
+    int mDimensionTag;
 
     std::map<HashableDimensionKey, int> mSlicedConditionState;
 
     void handleStopAll(std::vector<ConditionState>& conditionCache,
                        std::vector<bool>& changedCache);
 
-    void handleConditionEvent(const HashableDimensionKey& outputKey,
-                              bool matchStart,
-                              std::vector<ConditionState>& conditionCache,
-                              std::vector<bool>& changedCache);
+    void handleConditionEvent(const HashableDimensionKey& outputKey, bool matchStart,
+                              ConditionState* conditionCache, bool* changedCache);
 
     bool hitGuardRail(const HashableDimensionKey& newKey);