Date: Thu, 14 Oct 2004 13:48:12 -0400 From: Kenneth Culver <culverk@sweetdreamsracing.biz> To: fandino@ng.fadesa.es Cc: freebsd-questions@freebsd.org Subject: Re: FreeBSD and poor ata performance Message-ID: <20041014134812.sk484cooococg04w@www.sweetdreamsracing.biz> In-Reply-To: <416EB6B1.6060405@ng.fadesa.es> References: <416EB6B1.6060405@ng.fadesa.es>
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Quoting fandino <fandino@ng.fadesa.es>: > Hello list, > > This is an interesting issue. While I was installing FreeBSD 5.3BETA7 > I wonder about the performance that the new branch will bring to my > computer, and it was a deception how bad FreeBSD performs compared > with Linux on the same hardware (even I repeat the test on different PC > with identical results). > > A simple test is create one gibabyte file and later read this file again. To > conduct an impartial test the disk (in UDMA5 mode), was formated in both > operating systems with the native filesystem just to be sure that the > physical position of the file will be the same in both tests. > > for linux it took about 23 seconds write the file and 18 read it. > > # time dd if=/dev/zero of=aa bs=1024k count=1024 > 1024+0 records in > 1024+0 records out > > real 0m23.408s > user 0m0.000s > sys 0m4.470s > > # time dd if=aa of=/dev/null bs=1024k > 1024+0 records in > 1024+0 records out > > real 0m18.311s > user 0m0.000s > sys 0m5.850s > > and for FreeBSD it took 40 seconds write the file and 42 read it: > > # dd if=/dev/zero of=aa bs=1024k count=1024 > 1024+0 records in > 1024+0 records out > 1073741824 bytes transferred in 40.143630 secs (26747502 bytes/sec) > > # dd if=aa of=/dev/null bs=1024k > 1024+0 records in > 1024+0 records out > 1073741824 bytes transferred in 42.711242 secs (25139560 bytes/sec) > > so as you can see linux was two times faster that FreeBSD :-? > I would like to know if anyone knows if this is normal or > is a bug? > > thank you. > FreeBSD might be slower at using /dev/zero.... it might not be the ata performance. I've never seen any problem with FreeBSD's ata performance on my hardware. Ken
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