Date: Tue, 01 Dec 2009 17:16:17 +0200 From: Alexander Motin <mav@FreeBSD.org> To: "O. Hartmann" <ohartman@zedat.fu-berlin.de> Cc: FreeBSD Stable <freebsd-stable@freebsd.org>, freebsd-questions@freebsd.org Subject: Re: Phoronix Benchmarks: Waht's wrong with FreeBSD 8.0? Message-ID: <4B153341.3060909@FreeBSD.org> In-Reply-To: <1259583785.00188644.1259572202@10.7.7.3> References: <1259583785.00188644.1259572202@10.7.7.3>
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O. Hartmann wrote: > I'm just wondering what's wrong with FreeBSD 8.0/amd64 when I read the > Benchmarks on Phoronix.org's website. Especially FreeBSD's threaded I/O > shows in contrast to all claims that have been to be improoved the > opposite. Instead of trying to compare something, I propose to look on that numbers itself first: - first test tells that average write latency is about 100us. But it looks quite surprising for Laptop HDD, which has seek time of at least several milliseconds. - second test - a bit closer to life - 2-3ms - ok, Linux won here slightly, as FreeBSD installation in this test had no NCQ support. - third test - 9us per write on Linux. I am just crying. - forth test - all OSes gave 50-80us. Probably it is just a buffer case read time. So most of shown cases are testing almost only file system cache parameters. It is just insane to compare them for so different systems with so different write-back policies. If somebody still have questions, after some UFS parameters tuning I've got with the same tiotest tool: - Random Write latency - 15us, - Random Read latency - 7us. So who can beat my FreeBSD? :))) What's about second test. To check possible NCQ effect I've built test setup with new 320GB 7200RPM Seagate drive connected to Intel ICH10R controller. I've run IMHO more reasonable benchmark/raidtest tool from ports on whole device, to execute pregenerated random mix of 10000 random-sized (512B - 128KB) read/write requests using default ata(4) driver and new ahci(4): Number of READ requests: 5029. Number of WRITE requests: 4971. Number of bytes to transmit: 655986688. Number of processes: 32. The results: ata(4) - no NCQ: Bytes per second: 12455402 Requests per second: 189 ahci(4) - with NCQ: Bytes per second: 19889778 Requests per second: 303 Results are repeatable up to the 4-th digit. Average time per request is 5.29ms and 3.3ms respectively, that is realistic for this drive. So, with such difference, I believe, we will not loose this test any more. -- Alexander Motin
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