Performance numbers?

Ivan Voras ivoras at freebsd.org
Fri Jan 30 12:55:03 PST 2009


Eric Anderson wrote:
> Hi GEOMers!
> 
> Does anyone have any benchmarks or numbers relating to GEOM performance?
> 
> I tried doing some on my own, but I didn't get very satisfactory
> results, so I'm curious what others have seen or used.
> 
> My hardware is a Core 2 Quad, with 4GB of ram.
> 
> First, I made an mdconfig'ed malloc backed 'disk' of 1.5GB.  Then, I
> tried running such tools as rawio, and diskinfo.  rawio fails with
> input/output errors, and diskinfo wants a larger device to give the full
> stats.  I ended up using purely dd since that worked.  Interestingly
> enough, dd'ing to the malloc device results in about 1000 operations per
> second, regardless of a blocksize of 512bytes or 1MB.

It's a good idea for testing.

1000 ops/s looks suspiciously like HZ, though I don't know why HZ would
influence GEOM (AFAIK context switches between threads, including GEOM
threads do not depend on it) - can you try ruling out HZ?

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