Speakerlist was taking a ridiculous amount of frame time when displaying large groups.

indra/llui/llscrolllistctrl.cpp

@@ -502,12 +502,14 @@ BOOL LLScrollListCtrl::addItem( LLScrollListItem* item, EAddPosition pos, BOOL r
 	
 		case ADD_SORTED:
 			{
-				// sort by column 0, in ascending order
-				std::vector<sort_column_t> single_sort_column;
-				single_sort_column.push_back(std::make_pair(0, TRUE));
-
 				mItemList.push_back(item);
-				std::stable_sort(mItemList.begin(), mItemList.end(), SortScrollListItem(single_sort_column,mSortCallback));
+				// std::stable_sort is expensive. Only do this if the user sort criteria is not column 0, otherwise 
+				// setNeedsSort does what we want.
+				if (mSortColumns.empty() || mSortColumns[0].first != 0)
+				{
+					// sort by column 0, in ascending order
+					std::stable_sort(mItemList.begin(), mItemList.end(), SortScrollListItem({ {0,true} }, mSortCallback));
+				}
 
 				// ADD_SORTED just sorts by first column...
 				// this might not match user sort criteria, so flag list as being in unsorted state

indra/llui/llscrolllistctrl.h

@@ -369,6 +369,7 @@ public:
 		return mSortCallback->connect(cb);
 	}
 
+	S32				getLinesPerPage();
 
 protected:
 	// "Full" interface: use this when you're creating a list that has one or more of the following:
@@ -405,7 +406,6 @@ private:
 	void			deselectItem(LLScrollListItem* itemp);
 	void			commitIfChanged();
 	BOOL			setSort(S32 column, BOOL ascending);
-	S32				getLinesPerPage();
 
 	S32				mLineHeight;	// the max height of a single line
 	S32				mScrollLines;	// how many lines we've scrolled down