#7603 HIGH 8.2.0 (: 2.6.25 audio performance regression

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#7603: 2.6.25 audio performance regression
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   Reporter:  dsd       |       Owner:  dilinger                           
       Type:  defect    |      Status:  new                                
   Priority:  high      |   Milestone:  8.2.0 (was Update.2)               
  Component:  kernel    |     Version:  not specified                      
 Resolution:            |    Keywords:  joyride-2181:- 8.2.0:? blocks:8.2.0
Next_action:  diagnose  |    Verified:  0                                  
  Blockedby:            |    Blocking:                                     
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Comment(by dsaxena):

 Replying to [comment:41 veplaini]:
 > With joyride-2273 not much improvement in the midi-tests; however
 > using the --sched option for csound really makes a difference: only
 > 1 xrun in rain.mid where there were loads.
 >
 > However --sched only works under su/sudo, as it can't lock memory
 > as user OLPC. This could be worked around so that the right permissions
 > are given to an 'audio' group, perhaps?

 --sched currently both sets the priority and locks memory. Is it possible
 to make these into two separate ops, at least for testing purposes? (we
 may want to take this discussion offline).

 > This might not be necessary if we have a more responsive kernel. I'm
 > really happy you are looking into this: previously I had the impression
 > RT preemption for olpc was a no-go area. I think this is crucial for
 > a laptop that will use media heavily.

 Note that we're not going to even consider -rt for the 8.2 update at this
 point as it would invalidate all our testing so far.  Have you done your
 csound testing with the kernel patch in [#comment:32 comment 32]?

 Thanks for the list, I'll go join.

-- 
Ticket URL: <http://dev.laptop.org/ticket/7603#comment:43>
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