Very slow umass in 6.2-RC2

[Kevin Oberman]

> From: Ivan Voras <ivoras at fer.hr>
> Date: Thu, 15 Feb 2007 19:12:40 +0100
> Sender: owner-freebsd-stable at freebsd.org
> 
> Alexander Shikoff wrote:
> 
> > umass0: vendor 0x1005 USB FLASH DRIVE, rev 2.00/1.00, addr 2
> > da0 at umass-sim0 bus 0 target 0 lun 0
> > da0: < USB FLASH DRIVE 34CH> Removable Direct Access SCSI-0 device
> > da0: 40.000MB/s transfers
> > da0: 3936MB (8060928 512 byte sectors: 255H 63S/T 501C)
> > 
> > Writing to this device is very slooooow.
> > 
> > Time taken to copy file of 1,4G is near 30 min.
> 
> 1400/1800=0.77... which looks suspiciously like the rate I get while
> copying over USB 1 port. What does "iostat 1" say while you're copying
> the file?

Looks a lot like a new 4GB drive I bought. It is painfully slow.

Here is the result of iostat:
      tty             ad0              da0            pass0             cpu
 tin tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
   0   77 16.00   1  0.02   4.00  48  0.19   0.00   0  0.00   0  0  1  0 99
   0  231  0.00   0  0.00   4.00  48  0.19   0.00   0  0.00   3  0  1  2 94
   0  649  0.00   0  0.00   4.00  36  0.14   0.00   0  0.00   3  0  2  2 94
   0   77  9.00   2  0.02   4.00   1  0.00   0.00   0  0.00   2  0  1  1 97
   0   77  9.00   2  0.02   0.00   0  0.00   0.00   0  0.00   4  0  1  0 95
 
This is (obviously) from the end of the transfer. Transfer rate varies
from .14 to .19 MB/s. While I have not one statistical analysis, it is
clear that the mode is .14 and I'd guess the median is around 16
KB/s. (I calculated it over 20 samples in the middle of the transfer.)

To say that this is dreadful is a major understatement, but I suspect it
is an issue with the drive. I will try it on Windows and see it it works
any better there. It might be crappy hardware. (At $30 for a 4GB drive,
it was certainly cheap.)
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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