tcpdump mailing list archives

Re: capturing on both interfaces simultaneously


From: "David Laight" <David.Laight () ACULAB COM>
Date: Mon, 12 Dec 2011 11:59:12 -0000

 
Is poll() better than select ?

poll() and select() use the same basic kernel code.
poll() is generally better since it doesn't have problems
with high numbered fds, and doesn't require a sparse
fd map to be scanned.

The linux libpcap has a poll() in the 'memory mapped'
kernel interface (in order to check for errors).
If the application is using poll() this is an unnecessary
system call.

I also think that interface could defer freeing the last
rx buffer until the request to read another packet.
That would avoid the necessity of a buffer copy
for applications that don't want to use callbacks.

        David


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