[ofa-general] [PATCH] opensm: multi lid routing balancing for updn/minhop

[Al Chu]

Fixed up one more typo ..

Al

On Mon, 2008-03-03 at 15:15 -0800, Al Chu wrote:
> Hey Sasha,
> 
> I just noticed a comment typo.  Here's a fixed patch :P
> 
> Al
> 
> On Mon, 2008-03-03 at 15:08 -0800, Al Chu wrote:
> > Hey Sasha,
> > 
> > I was originally going to submit this later on, but given the recent
> > "rebalancing switch connections" threads, I figure perhaps was now a
> > good time to post this patch.
> > 
> > When we turn on lmc > 0, we noticed that sometimes extra lids from a
> > port would be forwarded through one parent switch than another.  For
> > example, suppose LMC = 2 and we are trying to route lids (1,2,3,4).  The
> > lids can be forwarded out of 8 ports, which go to two different
> > switches.  We would see something like this:
> > 
> > switch port 1 (to switch A): 1
> > switch port 2 (to switch A): 3
> > switch port 3 (to switch A): 4
> > switch port 4 (to switch A):
> > switch port 5 (to switch B): 2
> > switch port 6 (to switch B)
> > switch port 7 (to switch B):
> > switch port 8 (to switch B):
> > 
> > This occurs because the routing for LMC only favors those sys_guids and
> > node_guids that have not been seen before.  But it does not consider how
> > many times we have routed through a sys_guid/node_guid before.
> > 
> > The patch is fairly straight forward.  We just count how many times we
> > have forwarded to a sys_guid/node_guid before.  If there is a port that
> > has an equal number of paths to another port, but has not been forwarded
> > out as much, we pick that port.  Most of the patch is architectural
> > changes.  I stuff the sys_guid, node_guid, and a counter inside one
> > struct and array, because we can't count properly using the multiple
> > uint64_t arrays from before.
> > 
> > Thanks,
> > Al
> > 
> > _______________________________________________
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> > general at lists.openfabrics.org
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> > 
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-- 
Albert Chu
chu11 at llnl.gov
925-422-5311
Computer Scientist
High Performance Systems Division
Lawrence Livermore National Laboratory
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