#7603 NORM 8.2.0 (: 2.6.25 audio performance regression

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#7603: 2.6.25 audio performance regression
-------------------------+--------------------------------------------------
   Reporter:  dsd        |       Owner:  dilinger              
       Type:  defect     |      Status:  new                   
   Priority:  normal     |   Milestone:  8.2.0 (was Update.2)  
  Component:  kernel     |     Version:  not specified         
 Resolution:             |    Keywords:  joyride-2181:- 8.2.0:?
Next_action:  never set  |    Verified:  0                     
  Blockedby:             |    Blocking:                        
-------------------------+--------------------------------------------------

Comment(by dsaxena):

 Replying to [comment:10 dsd]:
 > I think this is responsible:
 >
 http://gitweb.freedesktop.org/?p=hal/hal.git;a=commit;h=7430beeb6c6fd6c8e51c24df20fd53c526aed6e8

 So looks like couple of options here:

   * Back out the above change so we can do a custom hald build for now.
 Not the best long term solution but would gives us something that works
 now...

   * Fixup the above in  HAL so that if the battery device does have a
 uevent, we don't poke at it continuously.

   * The EC code should probably rewritten to it does not hold a lock and
 disable IRQs for so long, but this is also a long-term project, not
 something to get done by next wed's build.

 I'm looking into the non-hald pops right now. Installing update.1 and
 trying to see what has changed in TamTam. One commit that stands out:

 {{{
 ommit 35fdf3ba130c95f2528b38b54f6e4c9448540f4c
 Author: James <olpc at localhost.localdomain>
 Date:   Wed Feb 21 04:35:16 2007 -0500

     adding self-scheduler

 diff --git a/Util/Clooper/aclient.cpp b/Util/Clooper/aclient.cpp
 index f53655a..d5da736 100644
 --- a/Util/Clooper/aclient.cpp
 +++ b/Util/Clooper/aclient.cpp
 @@ -5,6 +5,7 @@
  #include <time.h>
  #include <unistd.h>
  #include <sys/time.h>
 +#include <sched.h>

  #include <vector>
  #include <map>
 @@ -18,7 +19,7 @@


  unsigned int SAMPLE_RATE = 16000;
 -snd_pcm_uframes_t PERIODS_PER_BUFFER = 4;
 +snd_pcm_uframes_t PERIODS_PER_BUFFER = 2;
  snd_pcm_uframes_t PERIOD_SIZE = (1<<8);

  static int setparams (snd_pcm_t * phandle )
 @@ -52,6 +53,23 @@ static int setswparams(snd_pcm_t *phandle)
      return 0;
  }

 +static void setscheduler(void)
 +{
 +       struct sched_param sched_param;
 +
 +       if (sched_getparam(0, &sched_param) < 0) {
 +               printf("Scheduler getparam failed...\n");
 +               return;
 +       }
 +       sched_param.sched_priority = sched_get_priority_max(SCHED_RR);
 :                                                +       if
 (!sched_setscheduler(0, SCHED_RR, &sched_param)) {
 +               printf("Scheduler set to Round Robin with priority
 %i...\n", sched_param.
 +               fflush(stdout);
 +               return;
 +       }
 +       printf("!!!Scheduler set to Round Robin with priority %i
 FAILED!!!\n", sched_para
 +}
 +
  static double pytime(const struct timeval * tv)
  {
      return (double) tv->tv_sec + (double) tv->tv_usec / 1000000.0;
 @@ -390,6 +408,8 @@ struct TamTamSound
              buf[i*2] = buf[i*2+1] = 0.5 * sin( i / (float)nframes * 10.0
 * M_PI);
          }

 +        setscheduler();
 +
          while (PERF_STATUS == CONTINUE)
          {
              int err = 0;
 }}}

-- 
Ticket URL: <http://dev.laptop.org/ticket/7603#comment:14>
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