On Thu, 18 Jan 2001, Andi Kleen wrote:
> It is when you go to "dump netlink state every 60s" mode on overload.
60 esconds is way too long, but arguing about the length of polls isn't a
useful way to solve the problem. A good example for the characteristics
needed comes from the typical ISP setting. If an L2TP server goes down
for whatever reason and eventually comes back up, the system ends up with
several thousand users, perhaps tens of thousands, all reconnecting within
the same 3 second interval. If the connection takes more than a few
seconds to come up, then the user will disconnect and attempt to
reconnect -- presenting a further overload on the system (this is a real
world example a local ISP has encountered).
So far the shared memory idea sounds like it holds the most promise. I
could see having a series of device ids, states and generation #'s would
make the whole thing very efficient for both small and large state
changes.
-ben
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