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    SubjectLatency data - 2.6.14-rc3-rt13
    Hi,
    I'm still suffering the occasional xrun using Jack so I'm trying to
    understand what information I can feed back on this. I turned on the
    histogram feature for both IRQ-off and preempt-off. From what I can
    see so far it seems that something is turning IRQs off for long
    periods of time? I think that this is similar to what Lee Revell
    showed the other day, but I don't know how to get the same sort of
    printout he showed.

    This is the Jack data:

    nperiods = 2 for capture
    nperiods = 2 for playback
    08:16:26.401 Server configuration saved to "/home/mark/.jackdrc".
    08:16:26.401 Statistics reset.
    08:16:26.637 Client activated.
    08:16:26.639 Audio connection change.
    08:16:26.642 Audio connection graph change.
    08:16:28.395 MIDI connection graph change.
    08:16:28.472 MIDI connection change.
    08:16:29.664 Audio connection graph change.
    08:19:50.071 Audio connection graph change.
    08:19:50.263 MIDI connection graph change.
    08:19:50.273 MIDI connection graph change.
    10:04:36.179 Audio connection graph change.
    10:04:36.362 Audio connection change.
    10:04:38.800 Audio connection graph change.
    10:04:38.810 Audio connection graph change.
    12:34:09.601 XRUN callback (1).
    **** alsa_pcm: xrun of at least 0.133 msecs
    13:09:41.344 MIDI connection graph change.
    13:09:41.439 MIDI connection change.
    13:09:42.427 Audio connection graph change.
    13:09:45.919 Audio connection graph change.
    13:09:45.941 Audio connection graph change.
    13:09:45.960 MIDI connection graph change.

    This is what I see for preempt off latency. This looks really good to me:

    #Minimum latency: 0 microseconds.
    #Average latency: 0 microseconds.
    #Maximum latency: 1207040 microseconds.
    #Total samples: 196871313
    #There are 2 samples greater or equal than 10240 microseconds
    #usecs samples
    0 190504250
    1 5881275
    2 379533
    3 69966
    4 13858
    5 5708
    6 2287
    7 7726
    8 1771
    9 465
    10 649
    11 935
    12 948
    13 720
    14 573
    15 329
    16 139
    17 71
    18 46
    19 27
    20 21
    21 7
    22 3
    23 2
    24 1
    25 0
    26 0
    27 0


    However, for IRQ off latency I have far larger numbers. I Assume that
    it's probably pretty bad that interrupts could be turned off for as
    long as 4mS when I'm trying to run sub3mS?

    #Minimum latency: 0 microseconds.
    #Average latency: 4 microseconds.
    #Maximum latency: 3998 microseconds.
    #Total samples: 3102665680
    #There are 0 samples greater or equal than 10240 microseconds
    #usecs samples
    0 3066905198
    1 3817807
    2 15630448
    3 347330
    4 55362
    5 40098
    6 27080
    7 27740
    8 22484
    9 20298
    10 15727
    11 15346
    12 14870
    13 15258
    14 101559
    15 16152
    <SNIP>
    1365 18434
    1366 15529
    1367 12471
    1368 11392
    1369 13927
    1370 21813
    1371 39568
    1372 87654
    1373 250408
    1374 535990
    1375 577197
    1376 370609
    1377 120045
    1378 20431
    1379 5312
    1380 5349
    1381 8203
    1382 14773
    1383 15352
    1384 9515
    1385 5020
    1386 3618
    1387 3738
    1388 5554
    1389 8669
    1390 8244
    1391 6448
    1392 4948
    1393 4151
    1394 5984
    1395 10599
    1396 19058
    1397 41222
    1398 109732
    1399 360362
    1400 354579
    1401 113700
    1402 11014
    1403 1240
    1404 754
    1405 772
    1406 963
    1407 850
    1408 445
    1409 276
    <SNIP>
    3976 62
    3977 57
    3978 71
    3979 70
    3980 59
    3981 61
    3982 69
    3983 76
    3984 75
    3985 72
    3986 76
    3987 80
    3988 65
    3989 64
    3990 78
    3991 70
    3992 85
    3993 128
    3994 236
    3995 358
    3996 96
    3997 0
    3998 1
    3999 0
    4000 0
    4001 0
    4002 0


    How can I get data that would be more useful in terms of real debug?

    Thanks,
    Mark
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