On Tue, 01 Sep 2009 08:50:17 +0200
Eric Dumazet [off-list ref] wrote:

Stephen Hemminger a écrit :

quoted

Looking at the neighbour table, it should be possible to get
rid of the two reader/writer locks.  The hash table lock is pretty
amenable to RCU, but the dynamic resizing makes it non-trivial.
Thinking of using a combination of RCU and sequence counts so that the
reader would just rescan if resize was in progress.

I am not sure neigh_tbl_lock rwlock should be changed, I did not
see any contention on it.

quoted

The reader/writer lock on the neighbour entry is more of a problem.
Probably would be simpler/faster to change it into a spinlock and
be done with it.

The reader/writer lock is also used for the proxy list hash table,
but that can just be a simple spinlock.

This is probably is the only thing we want to do at this moment,
halving atomic ops on neigh_resolve_output()

But why neigh_resolve_output() was called so much in the bench
is the question...

Every packet has to have an ARP resolution.

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