#9593 LOW Future : XO-1 F11 slow USB transfer rate

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#9593: XO-1 F11 slow USB transfer rate
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           Reporter:  Quozl      |       Owner:  dsaxena       
               Type:  defect     |      Status:  new           
           Priority:  low        |   Milestone:  Future Release
          Component:  kernel     |     Version:  not specified 
         Resolution:             |    Keywords:                
        Next_action:  reproduce  |    Verified:  0             
Deployment_affected:             |   Blockedby:                
           Blocking:             |  
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Comment(by Quozl):

 Sure, good point.

 The commands used were based on ''cat'', ''pv'' and ''badblocks''.  There
 was not much difference between the programs in terms of data rate.  The
 XO-1.5 with os33 test results by command were:

 ||'''command'''||'''time'''||'''rate'''||
 ||cat||4min 15sec||15.0MB/s||
 ||pv||4min 9sec||15.4MB/s||
 ||pv||4min 7sec||15.5MB/s||
 ||badblocks||4min 6sec||15.6MB/s||

 The ''badblocks'' command was the fastest.  More details on these
 commands:

 = badblocks =

 {{{
 time badblocks /dev/sda
 }}}

 ''badblocks'' is included in the builds, and the program opens and reads
 the device itself.  The command reads from the device only, and does not
 write to /dev/null.

 = pv =

 {{{
 time /usr/local/bin/pv /dev/sda > /dev/null
 }}}

 ''pv'' is not included in the builds, but is installable on Debian, and
 can be copied and used in the builds without requiring any additional
 dependencies.  While reading from the device it writes to stderr (the
 screen) a progress chart updated at 1Hz.  The command reads from the
 device and writes to /dev/null.  On termination it displays a total time
 and overall data rate.  I checked that the displayed rate was correct
 against my calculations based on elapsed time.

 = cat =

 {{{
 time cat < /dev/sda > /dev/null
 }}}

 ''cat'' is included in the builds, and the program reads the file
 descriptor that was opened by the shell.  The command reads from the
 device and writes to /dev/null.

-- 
Ticket URL: <http://dev.laptop.org/ticket/9593#comment:2>
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