•Algorithmic Modifications
–Reducing double allocation
•One allocation by mutator and one by collector
•Deferring the double allocation
–Rooms and Better Rooms
•A push room and a pop room
•Only one room can be non-empty
•Rooms
–Enter the pop room, fetch work and perform, transition to thepush room, push objects back to the shared stack
–Graying objects is time-consuming
–Wait for entering the push room