In the attachment an implementation of SharedQueue3, which using atomic operation. Of course , currently it is based on assumption that some stuff (like two assignments in a row) can't be interrupted. The FIFO implementation using ASWP and CAS: push: - no spins, 1 ASWP pop: - 2 spins, 1 ASWP , 1 CAS Here a simple bench i made, which pushing 100000 elements into queue using 10 different processes, and then looks how many are popped via 3 feeder processes during that time: Squeak VM. SharedQueue : SharedQueue3Test new benchManyPushersAndFeeders: SharedQueue 'Added 100000 items, processed 30000 queue items during 1928 milliseconds' SharedQueue2 : SharedQueue3Test new benchManyPushersAndFeeders: SharedQueue2 'Added 100000 items, processed 30034 queue items during 1074 milliseconds' SharedQueue3 (mine) : SharedQueue3Test new benchManyPushersAndFeeders: SharedQueue3 'Added 100000 items, processed 70229 queue items during 118 milliseconds' Cog: SharedQueue3Test new benchManyPushersAndFeeders: SharedQueue 'Added 100000 items, processed 29999 queue items during 1955 milliseconds' SharedQueue3Test new benchManyPushersAndFeeders: SharedQueue2 'Added 100000 items, processed 29997 queue items during 197 milliseconds' SharedQueue3Test new benchManyPushersAndFeeders: SharedQueue3 'Added 100000 items, processed 100000 queue items during 26 milliseconds' if anyone has better ideas how to bench throughput, send me the code. -- Best regards, Igor Stasenko AKA sig.