[Lustre-devel] using LST for performance testing

Isaac Huang He.Huang at Sun.COM
Thu Oct 8 12:42:25 PDT 2009

On Tue, Sep 29, 2009 at 11:51:45AM -0500, Nic Henke wrote:
>   ......
> > The test servers concurrently posts one passive buffer for each
> > request, so for each test request there's one LNetMDAttach and one
> > unlink operation and both operations need to grab the one big
> > LNET_LOCK therefore it could be possible that the server CPU becomes a
> > bottleneck before the network could be saturated. The solution is to,
> > instead of one request per buffer, post one big buffer that could
> > accommodate multiple requests to amortize the per buffer processing
> > costs.
> >   
> If we added timestamps to the data, the processing time & buffer sizing 
> would be less of an issue - it wouldn't factor into the accuracy of the 
> numbers are are gathering.

Probably not. The timestamps affect only the stat gathering RPCs which
should be far out numbered by the test RPCs (loop x concurrency x
test_client_count, for each test server).


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