Date: Sun, 28 Jan 2007 19:02:01 -0500 From: =?ISO-8859-1?Q?Sten_Daniel_S=F8rsdal?= <sten.daniel.sorsdal@gmail.com> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-current@freebsd.org, Alexey Karagodov <karagodov@gmail.com>, Stefan Ehmann <shoesoft@gmx.net> Subject: Re: Interesting speed benchmarks Message-ID: <45BD3979.908@gmail.com> In-Reply-To: <200701261536.48893.hselasky@c2i.net> References: <20070125.192448.-432840241.imp@bsdimp.com> <cb5206420701260435s66e0687bnb467a42379d0a8d3@mail.gmail.com> <200701261341.03742.shoesoft@gmx.net> <200701261536.48893.hselasky@c2i.net>
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Hans Petter Selasky wrote: > On Friday 26 January 2007 13:41, Stefan Ehmann wrote: >> On Friday 26 January 2007 13:35, Andrew Pantyukhin wrote: >>> On 1/26/07, Stefan Ehmann <shoesoft@gmx.net> wrote: >>>> On Friday 26 January 2007 11:00, Alexey Karagodov wrote: >>>>> what manufacturer says about usb speeds? >>>>> that is the question >>>> Well, "up to 56MB/s" which is pretty much full USB2 speed. >=20 > It is called high speed USB, and it can go up 53 MB/s with a payload of= 512=20 > bytes per packet according to "Table 5-10. High-speed Bulk Transaction = > Limits" in the USB 2.0 specification. The table does not say anything a= bout=20 > whether this include bit-stuffing or not. If bit stuffing is not includ= ed,=20 > then you have to divide this value by 1.20 approximately for the worst = case,=20 > all 1's. 53 MB/s div 1.20 =3D 44 MB/s. >=20 >>>> But writing it on the box doesn't mean the speed can actually be >>>> reached. >>>> >>>> Benchmarking on windows might be interesting, but I don't know how t= o >>>> measure raw disk io on windows. >>> Format the disk, copy a large file to/from it, divide >>> its size by time spent, add the word "approximately" :-) >> I'd rather not format a drive with my backups and other stuff on it :-= ) >=20 > Results with the new USB stack*: >=20 > Changing the interrupt delay from 2 microframes to 1 microframe gave me= =20 > 2MBytes more per second on the EHCI controller. >=20 > I connected two high speed "umass" capable devices to the same EHCI con= troller=20 > on my computer, and did a "dd" on both devices at the same time, with a= block=20 > size of 131072 bytes. >=20 > The one device transferred 22 MB/s. The other device transferred 16 MB/= s.=20 > Summed up this yields 38 MB/s. Used alone these devices can transfer 27= MB/s=20 > and 20 MB/s. It seems clear that the EHCI controller is saturated at 38= MB/s.=20 >=20 > %dmesg |grep ehci > ehci0: <Intel 82801DB/L/M (ICH4) USB 2.0 controller> mem 0xe0100000-0xe= 01003ff=20 > irq 10 at device 29.7 on pci0 > usb3: <Intel 82801DB/L/M (ICH4) USB 2.0 controller> on ehci0 > % >=20 Just FYI. I get about the same performance on my laptop running Windows XP when moving between local 100 mb 5400 rpm ATA and 250 mb 7200 rpm USB2.0 disk.= I have the same controller. --=20 Sten Daniel S=F8rsdal
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