On Mon, Sep 13, 2010 at 03:21:13PM -0700, David Christensen wrote: > > I'm under the impression the header splitting in bce(4) is for > > LRO(opposite of TSO), not for VM magic to enable page flipping > > tricks. > > Header splitting was implemented in the Linux version of bce(4) > to prevent jumbo memory allocations. Allocating 9KB frames was > causing problems on systems used for virtualization. (Harder to > find a contiguous 9KB frame when a hypervisor is in use.) Using > 4KB or smaller buffer sizes was considered more compatible with > virtualization. > > LRO (Large Receive Offload, aka Transparent Packet Aggregation > or TPA on the 10Gb controllers) is not supported on the 1Gb > bce(4) devices. >
I meant tcp_lro implementation of FreeBSD. ATM tcp_lro_rx() runs long list of sanity checks before combining TCP segments into a TCP segment but if TCP header is split with its payload I guess we can optimize that path. This way we may be able to support LRO over VLAN, I guess. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
