[Click] dynamic changes to a click configuration

[Mike Wilson]

On Sun, 18 Mar 2007, Eddie Kohler wrote:

> Mike,
>
> You do know that you can install a new configuration without killing Click, 
> right?

No, I didn't - which makes me very glad I asked, since I think this may 
make my life much, much easier!

> And the "hotswap" feature (click-install -h) will install a new configuration 
> without losing any packets in Queue and FromDevice elements, assuming the new 
> & old elements have the same name.  There may be a performance hiccup, but 
> only small, and you should measure to see.

The performance problem is insignificant for my needs.

Presumably packets in any queues that *do* disappear will be dropped, 
right?  I'd consider this to be correct behavior, and it also matches my 
needs.

Looking at click -R, does this give the same hot-swap capability in user 
space as in the kernel?  It looks as if it does, by way of a ControlSocket 
and WRITEDATA hotconfig <bytecount>\n <new config>

Thanks, Eddie - I think you just saved me at least 2 weeks of solid 
hacking up a prototype I'd only need to throw away later.

-Mike Wilson