Differences between FastClick and Click

Core

• Support for batching
• Thread vectors, allowing easier thread management

I/O

• The (reverted from FastClick) DPDK version in mainline is very limited (no native multi-queue, you have to duplicate elements etc)
• The Netmap version in mainline was less efficient, and less up-to-date. Though frankly we stopped using Netmap here a while ago. Today NICs are not only about receiving a packet, but also offloading, rule classification, etc. DPDK is much better at that.

Features

• The flow subsystem that comes from MiddleClick and allow to use many classification algorithm for new improved NAT, Load Balancers, DPI engine (HyperScan, SSE4 string search), Statistics tracking, etc
• Many new elements
• Many elements made thread-safe and batch-native
• A lot of locking and multithreading facilities in multithread.hh, and a thread-safe HashTable in hashtablemp.hh (but it was tested for x86 only)
• If TSCClock is placed in the configuration, time calls will use the TSC directly from userlevel and will not use the much slower vDSO.
• Same for JiffieClick, to use a counter instead of dividing the time.

Default compilation options

• By defaults FastClick compiles with userlevel multithread. You still have to explicitely --enable-dpdk if you want fast I/O with DPDK (you do)