Date: Tue, 3 Feb 2009 07:06:36 -0600 From: Eric Anderson <anderson@vnode.org> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-geom@freebsd.org Subject: Re: Performance numbers? Message-ID: <4E34132B-9EFF-4108-8E50-80A5CE186EAB@vnode.org> In-Reply-To: <gm6dlq$lcj$1@ger.gmane.org> References: <6612C205-C346-4493-9DA4-3B5A73E9A4F7@freebsd.org> <glvp7l$6td$3@ger.gmane.org> <9C533E30-BD08-4938-8D1A-5CE046FB6BF6@freebsd.org> <gm6dlq$lcj$1@ger.gmane.org>
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On Feb 2, 2009, at 3:16 AM, Ivan Voras wrote: > Eric Anderson wrote: >> >> 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? > > You could use gzero, it ignores written data and produces read data > with > memset. Ok, I tried gzero, and now the numbers are *much* different. I'm getting roughly 60,000 ops/s now single threaded, or about 140,000 ops/ s using 4 threads. Much better! :) I could not for the life of me remember geom_zero, so thanks for the reminder. > > >> Also, are you thinking setting the hz to some other setting, and >> rerunning? What setting were you thinking? I can easily try >> anything. > > Yes. Try 1500. > I think I'll skip that now that I have gzero working giving me more realistic numbers. Eric
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