Date: Sun, 1 Feb 2009 20:48:06 -0600 From: Eric Anderson <anderson@freebsd.org> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-geom@freebsd.org Subject: Re: Performance numbers? Message-ID: <9C533E30-BD08-4938-8D1A-5CE046FB6BF6@freebsd.org> In-Reply-To: <glvp7l$6td$3@ger.gmane.org> References: <6612C205-C346-4493-9DA4-3B5A73E9A4F7@freebsd.org> <glvp7l$6td$3@ger.gmane.org>
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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 >> 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? > 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. Thanks! Eric
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