Date: Fri, 26 Jan 2007 13:09:30 -0600 From: Eric Anderson <anderson@freebsd.org> To: Warner Losh <imp@bsdimp.com> Cc: freebsd-current@freebsd.org, shoesoft@gmx.net Subject: Re: Interesting speed benchmarks Message-ID: <45BA51EA.3070901@freebsd.org> In-Reply-To: <20070126.114944.104080809.imp@bsdimp.com> References: <20070125.192448.-432840241.imp@bsdimp.com> <200701261052.12435.shoesoft@gmx.net> <20070126.114944.104080809.imp@bsdimp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 01/26/07 12:49, Warner Losh wrote: > From: Stefan Ehmann <shoesoft@gmx.net> > Subject: Re: Interesting speed benchmarks > Date: Fri, 26 Jan 2007 10:52:11 +0100 > >> On Friday 26 January 2007 03:24, M. Warner Losh wrote: >>> On a lark, I just got a combo USB/Firewire external disk drive. I ran >>> some crude benchmarks, and I was surprised by what I found. This is >>> on a fairly stock -current kernel. >>> >>> Firewire does around 40MB/s, while USB 2.0 maxes out at about 12MB/s. >>> This is with a simple dd command: >> On my i386 notebook with USB 2.0 enclosure. >> Linux: 31.5MB/s >> FreeBSD: 27.5MB/s >> >> There's still room for improvement but numbers don't seem that bad. >> >> Maybe you should try knoppix or so to verify it's not the drive's fault. Other >> than that I'd also guess it's an amd64 problem. > > It is not an AMD64 problem. I get the same numbers on my i386 latpop > as I get on my amd64 laptop. Actually, I get WORSE numbers on the > i386 laptop by about 20%. > > It isn't the drive's fault. Otherwise, firewire wouldn't get 40MB/s. > The same drive, the same enclusure are used for both the USB and > firewire tests. It is about as apples to apples as you can get. > > There's some serious performance issues in the usb stack. > > Warner A few tidbits of information (may be useful, maybe not): - I've seen the firewire part of the enclosure be faster than the USB part. The chips that run it are possibly different, so that shouldn't be forgotten. I've had a few USB->flash adapters that got lousy performance, but when I switched to a USB->SATA flash card reader, the performance doubled. - For those testing using a file system - STOP! It's not a good test of the throughput of the device, and depends on a lot of variables. dd or diskinfo are decent generic tools, but in Windows you just can't use a file system benchmark to compare. - If you read/write less than the drive cache, it should remove the latency of the drive from the equation, right? Eric
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?45BA51EA.3070901>