We have a new microbenchmark RemoveMicroBenchmark, that demonstrates that bulk remove operations in LinkedTransferQueue scale quadratically, while clear() scales linearly.

/home/martin/jdk/jdk9/bin/java -XX:+UseParallelGC RemoveMicroBenchmark filter=TransferQueue warmup=0 size=100
Method Millis Ratio
LinkedTransferQueue .removeIf 369 1.000
LinkedTransferQueue .removeAll 329 0.892
LinkedTransferQueue .retainAll 319 0.865
LinkedTransferQueue Iterator.remove 322 0.872
LinkedTransferQueue clear 80 0.218
/home/martin/jdk/jdk9/bin/java -XX:+UseParallelGC RemoveMicroBenchmark filter=TransferQueue warmup=0 size=200
Method Millis Ratio
LinkedTransferQueue .removeIf 4065 1.000
LinkedTransferQueue .removeAll 1126 0.277
LinkedTransferQueue .retainAll 1191 0.293
LinkedTransferQueue Iterator.remove 1233 0.303
LinkedTransferQueue clear 135 0.033
/home/martin/jdk/jdk9/bin/java -XX:+UseParallelGC RemoveMicroBenchmark filter=TransferQueue warmup=0 size=400
Method Millis Ratio
LinkedTransferQueue .removeIf 7134 1.000
LinkedTransferQueue .removeAll 4996 0.700
LinkedTransferQueue .retainAll 5078 0.712
LinkedTransferQueue Iterator.remove 4654 0.652
LinkedTransferQueue clear 301 0.042