5.1_RC3: reading from USB stick is very slow

[Aleksey Cheusov <cheusov%tut.by@localhost>]

On my machine read speed from USB stick under NetBSD 5.1_RC3
is less than ~4Mb/s (usb stick was plugged in during boot).

   asrock# dd if=/dev/rsd0d of=/dev/null bs=16k count=10000 
   10000+0 records in
   10000+0 records out
   163840000 bytes transferred in 40.004 secs (4095590 bytes/sec)
   asrock#

After plugging it out and in again speed is a bit higher

   asrock# dd if=/dev/rsd0d of=/dev/null bs=16k count=10000 
   10000+0 records in
   10000+0 records out
   163840000 bytes transferred in 30.005 secs (5460423 bytes/sec)
   asrock#

1) What causes this difference? Is it expected?
2) On the same hardware Linux Fedora-12 (2.6.31) Live CD shows speed about 
21Mb/s.
   Is this a problem of NetBSD USB stack or hardware is detected
   incorrectly? Does things change in CURRENT?

dmesg:
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008, 2009, 2010
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 5.1_RC3 (GENERIC) #1: Mon Jun 28 00:06:07 EEST 2010
        
cheusov%asrock.chizhovka.net@localhost:/srv/obj/sys/arch/amd64/compile/GENERIC
total memory = 1535 MB
avail memory = 1472 MB
timecounter: Timecounters tick every 10.000 msec
timecounter: Timecounter "i8254" frequency 1193182 Hz quality 100
SMBIOS rev. 2.6 @ 0xfb5c0 (21 entries)
To Be Filled By O.E.M. To Be Filled By O.E.M. (To Be Filled By O.E.M.)
mainbus0 (root)
cpu0 at mainbus0 apid 0: Intel 686-class, 1606MHz, id 0x106c2
cpu1 at mainbus0 apid 2: Intel 686-class, 1606MHz, id 0x106c2
cpu2 at mainbus0 apid 1: Intel 686-class, 1606MHz, id 0x106c2
cpu3 at mainbus0 apid 3: Intel 686-class, 1606MHz, id 0x106c2
ioapic0 at mainbus0 apid 4: pa 0xfec00000, version 11, 24 pins
acpi0 at mainbus0: Intel ACPICA 20080321
acpi0: X/RSDT: OemId <071709,RSDT1230,20090717>, AslId <MSFT,00000097>
acpi0: SCI interrupting at int 9
acpi0: fixed-feature power button present
timecounter: Timecounter "ACPI-Safe" frequency 3579545 Hz quality 900
ACPI-Safe 32-bit timer
pcppi1 at acpi0 (SPKR, PNP0800): io 0x61
midi0 at pcppi1: PC speaker (CPU-intensive output)
sysbeep0 at pcppi1
hpet0 at acpi0 (HPET, PNP0103-0): mem 0xfed00000-0xfed00fff irq 2,8
timecounter: Timecounter "hpet0" frequency 25000000 Hz quality 2000
attimer1 at acpi0 (TMR, PNP0100): io 0x40-0x43
WMI0 (pnp0c14) at acpi0 not configured
acpibut0 at acpi0 (PWRB, PNP0C0C-170): ACPI Power Button
attimer1: attached to pcppi1
pci0 at mainbus0 bus 0: configuration mode 1
pci0: i/o space, memory space enabled, rd/line, rd/mult, wr/inv ok
pchb0 at pci0 dev 0 function 0
pchb0: vendor 0x10de product 0x0a82 (rev. 0xb1)
vendor 0x10de product 0x0a88 (RAM memory, revision 0xb1) at pci0 dev 0 function 
1 not configured
pcib0 at pci0 dev 3 function 0
pcib0: vendor 0x10de product 0x0aad (rev. 0xb2)
vendor 0x10de product 0x0aa4 (RAM memory, revision 0xb1) at pci0 dev 3 function 
1 not configured
vendor 0x10de product 0x0aa2 (SMBus serial bus, revision 0xb1) at pci0 dev 3 
function 2 not configured
vendor 0x10de product 0x0a89 (RAM memory, revision 0xb1) at pci0 dev 3 function 
3 not configured
vendor 0x10de product 0x0aa3 (Co-processor processor, revision 0xb1) at pci0 
dev 3 function 5 not configured
ohci0 at pci0 dev 4 function 0: vendor 0x10de product 0x0aa5 (rev. 0xb1)
LUB0: Picked IRQ 16 with weight 0
ohci0: interrupting at ioapic0 pin 16
ohci0: OHCI version 1.0, legacy support
usb0 at ohci0: USB revision 1.0
ehci0 at pci0 dev 4 function 1: vendor 0x10de product 0x0aa6 (rev. 0xb1)
LUB2: Picked IRQ 18 with weight 0
ehci0: interrupting at ioapic0 pin 18
ehci0: BIOS has given up ownership
ehci0: EHCI version 1.0
ehci0: companion controller, 12 ports each: ohci0
usb1 at ehci0: USB revision 2.0
hdaudio0 at pci0 dev 8 function 0: HD Audio Controller
LAZA: Picked IRQ 20 with weight 0
hdaudio0: interrupting at ioapic0 pin 20
hdafg0 at hdaudio0 vendor 0x1106 product 0x0397 nid 0x01 (firmware 
configuration)
hdafg0: DAC0:10, Analog Speaker: Jack (Green, 1C)
hdafg0: ADC1:13, Analog Mic In: Jack (Pink, 1A)
hdafg0: ADC1:13, Analog Line In: Jack (Blue, 1B)
hdafg0: DAC2:12, Digital SPDIF Out: Jack (Black, 20)
hdafg0: 2ch/2ch 48000Hz 16/16*
audio0 at hdafg0: full duplex, playback, capture, independent
hdafg1 at hdaudio0 vendor 0x10DE product 0x0007 nid 0x01 (firmware 
configuration)
hdafg1: DAC0:04, Digital Digital Other Out: Jack (Unknown, 05)
hdafg1: 2ch/0ch 48000Hz 16/16*
audio1 at hdafg1: full duplex, playback, capture, independent
ppb0 at pci0 dev 9 function 0: vendor 0x10de product 0x0aab (rev. 0xb1)
pci1 at ppb0 bus 2
pci1: no spaces enabled!
nfe0 at pci0 dev 10 function 0: vendor 0x10de product 0x0ab0 (rev. 0xb1)
LMAC: Picked IRQ 21 with weight 0
nfe0: interrupting at ioapic0 pin 21
nfe0: Ethernet address 90:e6:ba:25:46:eb
rgephy0 at nfe0 phy 3: RTL8169S/8110S/8211 1000BASE-T media interface, rev. 2
rgephy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto
ahcisata0 at pci0 dev 11 function 0: vendor 0x10de product 0x0ab9
LSA0: Picked IRQ 22 with weight 0
ahcisata0: interrupting at ioapic0 pin 22
ahcisata0: AHCI revision 1.2, 6 ports, 32 command slots, features 0xe222e020
atabus0 at ahcisata0 channel 0
atabus1 at ahcisata0 channel 1
atabus2 at ahcisata0 channel 2
atabus3 at ahcisata0 channel 3
atabus4 at ahcisata0 channel 4
atabus5 at ahcisata0 channel 5
ppb1 at pci0 dev 16 function 0: vendor 0x10de product 0x0aa0 (rev. 0xb1)
pci2 at ppb1 bus 1
pci2: i/o space, memory space enabled, rd/line, wr/inv ok
vga0 at pci2 dev 0 function 0: vendor 0x10de product 0x087d (rev. 0xb1)
wsdisplay0 at vga0 kbdmux 1: console (80x25, vt100 emulation)
wsmux1: connecting to wsdisplay0
drm at vga0 not configured
isa0 at pcib0
pckbc0 at isa0 port 0x60-0x64
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
uhub0 at usb0: vendor 0x10de OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 6 ports with 6 removable, self powered
uhub1 at usb1: vendor 0x10de EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub1: 6 ports with 6 removable, self powered
ahcisata0 port 0: device present, speed: 3.0Gb/s
ahcisata0 port 1: device present, speed: 1.5Gb/s
wd0 at atabus0 drive 0: <ST9320325AS>
wd0: drive supports 16-sector PIO transfers, LBA48 addressing
wd0: 298 GB, 620181 cyl, 16 head, 63 sec, 512 bytes/sect x 625142448 sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd0(ahcisata0:0:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133) 
(using DMA)
atapibus0 at atabus1: 1 targets
cd0 at atapibus0 drive 0: <Slimtype DVD A  DS8A3S, 906200301141, HP51> cdrom 
removable
cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
cd0(ahcisata0:1:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100) 
(using DMA)
uhidev0 at uhub0 port 3 configuration 1 interface 0
uhidev0: vendor 0x2101 product 0x020f, rev 1.00/0.01, addr 2, iclass 3/1
ukbd0 at uhidev0
umass0 at uhub1 port 6 configuration 1 interface 0
umass0: vendor 0x0930 USB Flash Memory, rev 2.00/1.00, addr 2
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
sd0 at scsibus0 target 0 lun 0: <, USB Flash Memory, 1.00> disk removable
sd0: fabricating a geometry
sd0: 1909 MB, 1909 cyl, 64 head, 32 sec, 512 bytes/sect x 3911616 sectors
sd0: fabricating a geometry
Kernelized RAIDframe activated
pad0: outputs: 44100Hz, 16-bit, stereo
audio2 at pad0: half duplex, playback, capture
boot device: wd0
root on wd0a dumps on wd0b
root file system type: ffs
wskbd1 at ukbd0 mux 1
wskbd1: connecting to wsdisplay0
uhidev1 at uhub0 port 3 configuration 1 interface 1
uhidev1: vendor 0x2101 product 0x020f, rev 1.00/0.01, addr 2, iclass 3/1
ums0 at uhidev1: 5 buttons and Z dir
wsmouse0 at ums0 mux 0
wsdisplay0: screen 1 added (80x25, vt100 emulation)
wsdisplay0: screen 2 added (80x25, vt100 emulation)
wsdisplay0: screen 3 added (80x25, vt100 emulation)
wsdisplay0: screen 4 added (80x25, vt100 emulation)
cd0: mbr partition exceeds disk size
umass0: at uhub1 port 6 (addr 2) disconnected
sd0: detached
scsibus0: detached
umass0: detached
umass0 at uhub1 port 6 configuration 1 interface 0
umass0: vendor 0x0930 USB Flash Memory, rev 2.00/1.00, addr 2
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
umass0: at uhub1 port 6 (addr 2) disconnected
probe(umass0:0:0:0): generic HBA error
scsibus0: detached
umass0: detached
umass0 at uhub1 port 6 configuration 1 interface 0
umass0: vendor 0x0930 USB Flash Memory, rev 2.00/1.00, addr 2
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
sd0 at scsibus0 target 0 lun 0: <, USB Flash Memory, 1.00> disk removable
sd0: fabricating a geometry
sd0: 1909 MB, 1909 cyl, 64 head, 32 sec, 512 bytes/sect x 3911616 sectors
sd0: fabricating a geometry

-- 
Best regards, Aleksey Cheusov.