On 11 Jan, Bruce M Simpson wrote: > On Fri, Jan 09, 2004 at 03:51:43PM -0600, Guy Helmer wrote: >> I want to look at memory-mapped access to the BPF device. >> This would preserve the existing network device drivers >> while reducing mbuf copies, context switches/user-kernel >> transitions, and latency. Performance ought to be >> comparable to Luca's approach, and this would also >> preserve bpf filtering capability. >> >> (If someone else has already done this, I'd love to >> know where to find the code!) > > I did review some patches related to this last month but they weren't > for FreeBSD. One big problem with the approach involved which leapt out > at me was that the space was allocated within user address space, which > introduces the risk of page faults (as you may know we can't ever fault > with a mutex held -- or it's game over).
You'd have to wire the buffer. Beyond a certain buffer size, you'd probably want to maintain a sliding window of of wired memory to avoid wiring an excessive amount of memory. _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
