anderson at freebsd.org
Sun Feb 1 18:48:09 PST 2009
On Jan 30, 2009, at 2:50 PM, Ivan Voras wrote:
> Eric Anderson wrote:
>> Hi GEOMers!
>> Does anyone have any benchmarks or numbers relating to GEOM
>> 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
>> 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
> influence GEOM (AFAIK context switches between threads, including GEOM
> threads do not depend on it) - can you try ruling out HZ?
Is there a way to pump the data through the GEOM layers without doing
a mdconfig'd disk?
Also, are you thinking setting the hz to some other setting, and
rerunning? What setting were you thinking? I can easily try anything.
More information about the freebsd-geom