[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[lwip-devel] [task #6849] Test how checksum on copy could be integrated
[lwip-devel] [task #6849] Test how checksum on copy could be integrated into the stack
Mon, 11 May 2009 16:09:10 +0000
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; de; rv:184.108.40.206) Gecko/2009042315 Firefox/3.0.10
Follow-up Comment #12, task #6849 (project lwip):
1) is done by telling lwIP to not care for creating/checking a specific
checksum (UDP, TCP, ICMP, IP). There are already defines for that.
2) would require a function tcp_enqueue_checksummed. I left that out in a
previous post but I would implement it just like udp_enqueue_checksummed.
Talking about efficiency: we can
a) let the application pre-calculate the checksum
b) create it when copying
c) create it in the driver
c) is obviously the best solution if the hardware supports on-the-fly
generation while copying the data using DMA. If not, it's not a good solution
Usage of a) and b) depend on the application: If you use TCP_NO_COPY or UDP
zero-copy (e.g. sockets), a) is of course better. If you copy anyway, the
overhead of an improved copy-and-checksum routine to a memcpy is minimal.
I'll try to create another patch for this to discuss about when I find the
Reply to this item at:
Nachricht geschickt von/durch Savannah