High Speed Capturing
Some ideas that might be worth trying out.
NTOP has customized drivers for DNA(Direct Network card Access), could something like that be made Open Source?
Luca Deri (author of NTOP) has contributed code to Wireshark in the past so he might be amenable. Otherwise, we could use Intel's DPDK directly - this too might require a license and permission, but Intel might be amenable for a tool like Wireshark.
Leaving some space at the beginning of the packet buffer to write the pcap(ng) header might avoid a copy and improve performance.
Having a pcap-ng phdr might be more efficient.
Doing benchmarking with libpcap(1.5.3) with the recently added AF_PACKET_V3 tcpdump was performing better than dumpcap. Possibly due to dumpcap using pcap_dispatch(pcap_opts->pcap_h, 1, capture_loop_write_packet_cb, (u_char *)pcap_opts); e.g just handling one packet at a time. If this could be rewritten to use -1 performance may be improved.