[Lustre-devel] faking LNET scale

Nic Henke nic at cray.com
Wed Apr 22 15:20:10 PDT 2009

Isaac Huang wrote:
> On Fri, Apr 17, 2009 at 12:10:01PM -0500, Nicholas Henke wrote:
>> ......
>> However, to do this either hacking up lnet_ptlcompat_matchXXX to look at another 
>> flag besides the_lnet.ln_ptlcompat or some other way of allowing a server with a 
>> single NET (ptl0) to accept requests from a variety of nets (ptl1, ptl2, etc). 
>> One cannot use multiple interfaces for the same net type with ln_ptlcompat enabled.
> Note that Portals compatibility (lnet_ptlcompat_, the_lnet.ln_ptlcompat, and friends)
> have already been removed from lnet HEAD, on which all 2.x and future releases will 
> be based.
>> 	Is there a better way to do this ? What would be the least abusive of th e rules ?
> If you only have limited number of test nodes, one way to drive the
> network as hard as possible is to have all nodes use a very high
> ptllnd peercredits option and run LST test with a high concurrency
> (with the latest LST patch from 15332).
> Thanks,
> Isaac
I was more interested in scaling the number of peers/connections. The
previous suggestion about doing a localnet check would help do that. 
>From past experience, we don't often find too many issues just getting
the data moving when changing to higher scale - it is all the mgmt of
peers/connections that end up getting 'fun'.

As you say - just using higher credits is usually sufficient to max out
the network throughput for a given set of nodes.


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