commit 356e28fdb19dcc6ecfa73c4b4f5a182978e7dd20
author Chris Jenneisch <chrisj@codeaurora.org> Mon Jan 08 13:34:09 2018 -0800
committer Shuzhen Wang <shuzhenwang@google.com> Wed Feb 28 23:14:31 2018 +0000
tree a21071a88d28c7306a04704ecc494405f6f28f92
parent b21613bd38d5341fd5d8738d6ff32bbac2c34360

Use std::unordered_map for mTagToTypeMap

In the profile we notice that  SortedVectorImpl::_indexOrderOf is
almost 1.6% which is quite high considering it is an access to
a container. We make mTagToNameMap as a std::unordered_map
to store the Tag and the types. The accesses would be in constant time.

This change removes this from the profile and give ~10% improvement.

Bug: 72526772
Change-Id: Iffd244febd093bdfec9fe4d5e846a0e59c0ecdce

camera/common/1.0/default/VendorTagDescriptor.cpp

diff --git a/camera/common/1.0/default/VendorTagDescriptor.cpp b/camera/common/1.0/default/VendorTagDescriptor.cpp
index bc18270..1f53857 100644
--- a/camera/common/1.0/default/VendorTagDescriptor.cpp
+++ b/camera/common/1.0/default/VendorTagDescriptor.cpp
@@ -116,11 +116,11 @@
 }
 
 int VendorTagDescriptor::getTagType(uint32_t tag) const {
-    ssize_t index = mTagToNameMap.indexOfKey(tag);
-    if (index < 0) {
+    auto iter = mTagToTypeMap.find(tag);
+    if (iter == mTagToTypeMap.end()) {
         return VENDOR_TAG_TYPE_ERR;
     }
-    return mTagToTypeMap.valueFor(tag);
+    return iter->second;
 }
 
 const SortedVector<String8>* VendorTagDescriptor::getAllSectionNames() const {
@@ -167,7 +167,7 @@
         String8 name = mTagToNameMap.valueAt(i);
         uint32_t sectionId = mTagToSectionMap.valueFor(tag);
         String8 sectionName = mSections[sectionId];
-        int type = mTagToTypeMap.valueFor(tag);
+        int type = mTagToTypeMap.at(tag);
         const char* typeName = (type >= 0 && type < NUM_TYPES) ?
                 camera_metadata_type_names[type] : "UNKNOWN";
         dprintf(fd, "%*s0x%x (%s) with type %d (%s) defined in section %s\n", indentation + 2,
@@ -251,7 +251,7 @@
             ALOGE("%s: tag type %d from vendor ops does not exist.", __FUNCTION__, tagType);
             return BAD_VALUE;
         }
-        desc->mTagToTypeMap.add(tag, tagType);
+        desc->mTagToTypeMap.insert(std::make_pair(tag, tagType));
     }
 
     desc->mSections = sections;

camera/common/1.0/default/include/VendorTagDescriptor.h

diff --git a/camera/common/1.0/default/include/VendorTagDescriptor.h b/camera/common/1.0/default/include/VendorTagDescriptor.h
index 8d8ded9..a040540 100644
--- a/camera/common/1.0/default/include/VendorTagDescriptor.h
+++ b/camera/common/1.0/default/include/VendorTagDescriptor.h
@@ -24,6 +24,7 @@
 #include <system/camera_vendor_tags.h>
 
 #include <stdint.h>
+#include <unordered_map>
 
 namespace android {
 namespace hardware {
@@ -94,7 +95,8 @@
         KeyedVector<String8, KeyedVector<String8, uint32_t>*> mReverseMapping;
         KeyedVector<uint32_t, String8> mTagToNameMap;
         KeyedVector<uint32_t, uint32_t> mTagToSectionMap; // Value is offset in mSections
-        KeyedVector<uint32_t, int32_t> mTagToTypeMap;
+
+        std::unordered_map<uint32_t, int32_t> mTagToTypeMap;
         SortedVector<String8> mSections;
         // must be int32_t to be compatible with Parcel::writeInt32
         int32_t mTagCount;