On Thu, Dec 06, 2007 at 11:18:37PM +0100, Renzo Davoli wrote:
No ethernet headers on localhost. Just to give you a perspective:
IP+TCP headers are 50 bytes (with timestamps) and IP+UDP is 28 bytes.
On the other hand the sk_buff+skb_shared_info header which are used for
all socket communication in Linux and have to be mostly set up always
are 192+312bytes on 64bit [parts of the 312 bytes is an array that is
typically only partly used] or 156+236 bytes on 32bit. So the network
headers dwarf the internal data structures.
There might be other reasons why TCP/IP is slower, but arguing
with the size of the headers is just bogus.
My personal feeling would be that if TCP/IP is too slow for something
it is better to just improve the stack than to add a completely
new socket family. That will benefit much more applications without
requiring to change them.
About the only good reason to use UNIX sockets is when you need to use
file system permissions.
IP Multicast when properly set up also doesn't need root.
Broadcast is kind of obsolete anyways.
They could easily just tunnel over a local multicast group for example.
-Andi
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