[Lustre-devel] using LST for performance testing

[Isaac Huang]

On Tue, Sep 29, 2009 at 01:32:48PM -0400, David Dillow wrote:
> On Tue, 2009-09-29 at 11:51 -0500, Nic Henke wrote:
> > I'm wondering if we couldn't add a new 'batch_stat' command. The idea is 
> > that the client code will fill in the start/stop times for each test and 
> > then after the test is done, 'batch_stat' would collect this data. The 
> > collection would still be passive and a new command should minimize the 
> > protocol changes. The per-test data would allow us to get accurate perf 
> > numbers and also provide some data into how parallel the tests were, if 
> > there are any unfairness issues, etc.
> 
> Along these lines, it would be nice if we could specify a run time for
> each test rather than an amount of data to be transferred -- it makes it
> easier to get aggregate bandwidth numbers, and often shows imbalances
> nicely -- the node getting starved is the one that transfers less data.

This would be a very useful feature. We're working on to add LST tests
to our automatic tests, where we met a problem that we could never
tell how long the test would run by looking at '--loop' and
'--concurrency'.

The LST already implemented a timer mechanism which is good at second
resolution, which should suffice for controlling test run time.

Isaac