Commit 31bf9b04 authored by Robert Ricci's avatar Robert Ricci
Browse files

Add some entries about recent assign changes.

parent b92a43a0
ricci 2003/07/01 10:14:42 MDT
Modified files:
assign anneal.h
assign_todo.txt pclass.h
Give assign the ability to make dynamic pclasses. Here's how it works:
After building the set of pclasses normally, we make another pass
through the vnodes. The goal to create a pclass for each individual
node. We disable the node's 'own' pclass to begin with. Then, the
_first_ time it gets a vnode mapped to it, we remove it from the
'regular' pclass it belongs to, and enable it's own pclass. Then, if
it goes empty, we put it back in its regular pclass and disable it's
The point of this is to replace -p for use with multiplexed nodes.
Instead of disabling pclasses altogheter, which has serious
performance implications, we can instead be smart about which pnodes
remain equivalent (because nothing's been mapped to them), and which
are now different. The result is that on my test topoloy, the time to
get a good mapping has gone from over 3 minutes to about 6 seconds.
This feature is enabled with the -d option, and the -P option is
pretty much mandatory when using it, since it greatly exacerbates the
problem of cruft in the ptop file.
This satisfies #14 from the todo file:
14. do dynamic pclasses
Also bumped up the minimum neighborhood size from 500 to 1000. In some
tests I was doing, this resulted in better solutions.
ricci 2003/06/26 13:13:16 MDT
Modified files:
assign anneal.h
assign_internals.txt physical.h
Major changes to the way assign handles LAN nodes.
LAN nodes are no longer treated specially. Instead, I've introduced
the idea of 'static' types (old-style types retroactively become
'dynamic' types). While a pnode can only satisfy one dynamic type at a
time, it can always satisfy its static types (assuming it has enough
capacity left.) Static types are flagged by prepending them with a '*'
in the ptop file. So, for example, you may give switches the
'*lan:10000' type so that they can satisfy virtual LAN nodes. Of
course, other pnodes can have this type too, so that we can get
'trivial LANs'.
Actually, removing special treatment for LANs cleans up a lot of code.
However, it may have some negative impacts on solutions, since we're
not as smart about where to place LAN nodes as we used to be (they get
annealed along with everything else, and not migrated.) I haven't seen
any evidence of this yet, however.
This leaves us with a single type of special pnode, a switch.
Also added a new bit of syntax in ptop files - when '*' is given as a
the maxiumum load for a type, the node is allowed to take on an
infinite (well, actually, just a really big number of) vnodes of that
ptopgen was modified to always report switches as being capable of
hosting LANs, and assign_wrapper now understands direct links to LANs,
which is what we get when the LAN is hosted directly on a switch.
Fixed a bug in scoring direct links, in which the penatly was being
added once when a direct link was mapped, but subtracted only once
when it was freed.
Added a '-T' option for doing simple self-testing. When adding a node
to the solution, assign records the score, adds the node, removes it
again, and checks to make sure that the resulting score is the same as
the original score. The usefulness of this feature in debugging
scoring problems cannot be understated...
stoller 2003/05/1 09:09:12 MDT
Modified files:
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