Date: Fri, 11 Sep 2015 08:04:05 -0400 From: Ernie Luzar <luzar722@gmail.com> To: freebsd-questions@freebsd.org Cc: Patrick Hess <patrickhess@gmx.net>, FreeBSD@ShaneWare.Biz, Dave <dave@dgmm.net> Subject: Re: USB physical ports Message-ID: <55F2C335.3030304@gmail.com> In-Reply-To: <2029052.xQsMmxkVaC@desk8.phess.net> References: <55F1A507.70402@gmail.com> <2091716.bhpPQfPjgk@amd.asgard.uk> <55F216CB.6040606@gmail.com> <2029052.xQsMmxkVaC@desk8.phess.net>
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Patrick Hess wrote: > Ernie Luzar wrote: >> How can I confirm 480Mbps transfer rate. > > Run "dmesg -a" after plugging in the device. A USB 2.0 flash drive > should be reported with a 40 MB/s transfer rate: > > da1: <Intenso Rainbow Line> Removable Direct Access SCSI-4 device > da1: 40.000MB/s transfers > > You can verify this by reading from the drive, e.g. by using dd(1): > > # dd if=/dev/da1 of=/dev/zero bs=1M count=1024 > 1024+0 records in > 1024+0 records out > 1073741824 bytes transferred in 52.099073 secs (20609615 bytes/sec) > > That's ~20 MB/s, definitely more than USB 1.x could have delivered. > Yes that is true, BUT it's a very long way from 480Mbps. Following are some test results. Before plugging in flash drive /root/bin >usbconfig ugen3.1: <EHCI root HUB Intel> at usbus3, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (0mA) ugen2.1: <UHCI root HUB Intel> at usbus2, cfg=0 md=HOST spd=FULL (12Mbps) pwr=SAVE (0mA) ugen1.1: <UHCI root HUB Intel> at usbus1, cfg=0 md=HOST spd=FULL (12Mbps) pwr=SAVE (0mA) ugen0.1: <UHCI root HUB Intel> at usbus0, cfg=0 md=HOST spd=FULL (12Mbps) pwr=SAVE (0mA) After plugging in flash drive /root/bin >usbconfig ugen3.1: <EHCI root HUB Intel> at usbus3, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (0mA) ugen2.1: <UHCI root HUB Intel> at usbus2, cfg=0 md=HOST spd=FULL (12Mbps) pwr=SAVE (0mA) ugen1.1: <UHCI root HUB Intel> at usbus1, cfg=0 md=HOST spd=FULL (12Mbps) pwr=SAVE (0mA) ugen0.1: <UHCI root HUB Intel> at usbus0, cfg=0 md=HOST spd=FULL (12Mbps) pwr=SAVE (0mA) ugen3.2: <Cruzer Blade SanDisk> at usbus3, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (200mA) Get this result no matter which physical port I plug into. Get these console messages when plugging in flash drive umass0: <SanDisk Cruzer Blade, class 0/0, rev 2.00/1.27, addr 2> on usbus3 umass0: SCSI over Bulk-Only; quirks = 0x8100 umass0:2:0:-1: Attached to scbus2 da0 at umass-sim0 bus 0 scbus2 target 0 lun 0 da0: <SanDisk Cruzer Blade 1.27> Removable Direct Access SPC-4 SCSI device da0: Serial Number 4C530001020404102235 da0: 40.000MB/s transfers da0: 14907MB (30529536 512 byte sectors: 255H 63S/T 1900C) da0: quirks=0x2<NO_6_BYTE> Why is it saying 40.000MB/s transfers? Is this some max value that Freebsd is limited to? /root/bin >dd if=/dev/da0 of=/dev/null bs=1M count=10 10+0 records in 10+0 records out 10485760 bytes transferred in 0.607835 secs (17250996 bytes/sec) /root/bin >dd if=/dev/da0 of=/dev/null bs=1M count=100 100+0 records in 100+0 records out 104857600 bytes transferred in 5.683069 secs (18450876 bytes/sec) /root/bin >dd if=/dev/da0 of=/dev/null bs=1M count=200 200+0 records in 200+0 records out 209715200 bytes transferred in 11.233349 secs (18668983 bytes/sec) /root/bin >dd if=/dev/da0 of=/dev/null bs=1M count=400 400+0 records in 400+0 records out 419430400 bytes transferred in 22.415176 secs (18711894 bytes/sec) If 20Mbps is the max rate Freebsd can do, then 18.7Mbps is a good rate. But the real question is why is Freebsd USB rates capped at 20Mbps when the hardware says it's capable of 480Mbps?
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