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. > > It is called high speed USB, and it can go up 53 MB/s with a payload of 512 > 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 about > whether this include bit-stuffing or not. If bit stuffing is not included, > then you have to divide this value by 1.20 approximately for the worst case, > all 1's. 53 MB/s div 1.20 = 44 MB/s. > >>>> 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 to >>>> 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 :-) > > Results with the new USB stack*: > > Changing the interrupt delay from 2 microframes to 1 microframe gave me > 2MBytes more per second on the EHCI controller. > > I connected two high speed "umass" capable devices to the same EHCI controller > on my computer, and did a "dd" on both devices at the same time, with a block > size of 131072 bytes. > > The one device transferred 22 MB/s. The other device transferred 16 MB/s. > Summed up this yields 38 MB/s. Used alone these devices can transfer 27 MB/s > and 20 MB/s. It seems clear that the EHCI controller is saturated at 38 MB/s. > > %dmesg |grep ehci > ehci0: <Intel 82801DB/L/M (ICH4) USB 2.0 controller> mem 0xe0100000-0xe01003ff > irq 10 at device 29.7 on pci0 > usb3: <Intel 82801DB/L/M (ICH4) USB 2.0 controller> on ehci0 > % > 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. -- Sten Daniel Sørsdalhelp
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