[LAU] 2.6.39.1 Xruns last longer!! (was: 2.6.39.1 threadirqs vs. the rest: some numbers)

Hi!

(hope the subject won't redirect this mail straight in your spam!)

I'm using 2.6.39 + thread irqs for several days/weeks, with FFADO
(Saffire PRO 40), on a moroless Debian system.

I'm really happy with it, it works fine, my DSP load is way lower than
before, and I don't have that Big Kernel Lock problem anymore, which is
cool.

But, when having an Xrun (which occurs very rarely, like once every 6 or
7 hours average), it last really long (I would say something like 2-5
seconds), and is thus highly hearable (sounds really stop, no unsync
clics, but a total silence).

I wondered whether someone had an explanation about this, as I can't
find a reason for that.

See you.
Aurélien

On Mon, Jun 13, 2011 at 05:38:11PM -0700, Fernando Lopez-Lezcano wrote :
> Hi all,
>
> I just built a threaded-irqs enabled 2.6.39.1 kernel and used
> cyclictest to try to get an initial feeling of how good it might be.
> Cyclictest tests scheduling delays of the kernel it is running
> on[*]. These tests were run on a Fedora 13 T510 Lenovo laptop, with
> the ugly binary Nvidia driver (caveat emptor).
>
> In the menu:
>
> 2.6.39.1 with threaded irqs and PREEMPT active
> 2.6.33.13-rt31
> 2.6.34.8-rt31 (a forward port of rt31 to 2.6.34)
> plain Fedora kernel (2.6.34.8-68.fc13.i686.PAE)
>
> Now, before someone points it out, this is just a synthetic test
> that measures scheduling latency, not a real audio application.
>
> See below for details... (look at the "Avg:" and "Max:" latency
> values, those are in microseconds)
>
> Unless I have done something wrong, it looks like we have a long way
> to go with regards to scheduling latency in anything other than
> 2.6.33 + rt patches. But, with threaded irqs in 2.6.39 maybe the
> performance with audio applications running under jack will be good
> anyway as we will be able to tune irq processing. Seems to me
> unlikely. I have not tested that yet.
>
> Tests were done after a clean reboot, initially with the machine
> idle and then while loading thunderbird with tons of emails and
> firefox with tons of pages. No audio work.
>
> YMMV...
> -- Fernando
>
> [*] https://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO
>
>
> ----------------------------------------------------------------------
> LENOVO T510
>
> ----------------------------------------------------------------------
> 2.6.33.13-149.rt31.2.fc13.ccrma.i686.rtPAE
> ----------------------------------------------------------------------
>
> $ while true ; do ./cyclictest -t1 -p 80 -n -i 10000 -l 10000 ; done
> policy: fifo: loadavg: 0.02 0.20 0.11 1/405 7024
>
> T: 0 ( 7024) P:80 I:10000 C: 10000 Min: 3 Act: 75 Avg: 54
> Max: 121
> policy: fifo: loadavg: 0.08 0.17 0.10 2/405 7027
>
> T: 0 ( 7026) P:80 I:10000 C: 10000 Min: 3 Act: 73 Avg: 75
> Max: 126
> policy: fifo: loadavg: 0.01 0.12 0.09 1/405 7029
>
> T: 0 ( 7029) P:80 I:10000 C: 10000 Min: 3 Act: 90 Avg: 49
> Max: 141
> policy: fifo: loadavg: 0.37 0.21 0.12 1/405 7031
>
> T: 0 ( 7031) P:80 I:10000 C: 10000 Min: 4 Act: 70 Avg: 76
> Max: 148
> policy: fifo: loadavg: 0.27 0.21 0.12 1/405 7033
>
> T: 0 ( 7033) P:80 I:10000 C: 10000 Min: 4 Act: 46 Avg: 73
> Max: 144
> policy: fifo: loadavg: 0.15 0.20 0.12 1/405 7035
>
> T: 0 ( 7035) P:80 I:10000 C: 10000 Min: 3 Act: 90 Avg: 77
> Max: 142
> policy: fifo: loadavg: 0.07 0.15 0.11 2/405 7037
>
> T: 0 ( 7037) P:80 I:10000 C: 10000 Min: 3 Act: 16 Avg: 71
> Max: 135
> policy: fifo: loadavg: 0.05 0.12 0.10 1/405 7040
>
> T: 0 ( 7039) P:80 I:10000 C: 10000 Min: 3 Act: 84 Avg: 72
> Max: 142
> policy: fifo: loadavg: 0.01 0.08 0.08 1/405 7042
>
> T: 0 ( 7042) P:80 I:10000 C: 10000 Min: 3 Act: 105 Avg: 51
> Max: 146
> policy: fifo: loadavg: 0.00 0.05 0.07 1/406 7045
>
> T: 0 ( 7044) P:80 I:10000 C: 10000 Min: 4 Act: 11 Avg: 50
> Max: 121
> policy: fifo: loadavg: 0.07 0.06 0.07 1/406 7047
>
> T: 0 ( 7047) P:80 I:10000 C: 10000 Min: 2 Act: 73 Avg: 76
> Max: 140
> policy: fifo: loadavg: 0.01 0.04 0.06 1/406 7049
>
> T: 0 ( 7049) P:80 I:10000 C: 10000 Min: 3 Act: 67 Avg: 70
> Max: 137
> policy: fifo: loadavg: 0.02 0.04 0.06 1/406 7051
>
> T: 0 ( 7051) P:80 I:10000 C: 9573 Min: 3 Act: 68 Avg: 47
> Max: 146
> policy: fifo: loadavg: 0.02 0.04 0.06 1/406 7053
>
> ----------------------------------------------------------------------
> 2.6.34.8-68.fc13.i686.PAE
> ----------------------------------------------------------------------
>
> $ while true ; do ./cyclictest -t1 -p 80 -n -i 10000 -l 10000 ;
> sleep 10; done
> policy: fifo: loadavg: 0.20 0.33 0.15 1/298 2559
>
> T: 0 ( 2521) P:80 I:10000 C: 10000 Min: 3 Act: 12 Avg: 36
> Max: 354
> policy: fifo: loadavg: 0.34 0.30 0.16 1/332 2676
>
> T: 0 ( 2583) P:80 I:10000 C: 10000 Min: 3 Act: 12 Avg: 31
> Max: 1749
> policy: fifo: loadavg: 0.39 0.38 0.20 1/350 2835
>
> T: 0 ( 2726) P:80 I:10000 C: 10000 Min: 2 Act: 9 Avg: 33
> Max: 12861
> policy: fifo: loadavg: 0.11 0.29 0.18 2/350 2839
>
> T: 0 ( 2838) P:80 I:10000 C: 10000 Min: 3 Act: 12 Avg: 43
> Max: 133
> policy: fifo: loadavg: 0.02 0.19 0.16 1/348 2842
>
> T: 0 ( 2842) P:80 I:10000 C: 10000 Min: 4 Act: 75 Avg: 48
> Max: 17789
> policy: fifo: loadavg: 0.07 0.15 0.14 1/347 2858
>
> T: 0 ( 2845) P:80 I:10000 C: 10000 Min: 4 Act: 56 Avg: 50
> Max: 1808
> policy: fifo: loadavg: 0.18 0.15 0.14 1/347 2861
>
> T: 0 ( 2861) P:80 I:10000 C: 10000 Min: 3 Act: 11 Avg: 52
> Max: 187
> policy: fifo: loadavg: 0.34 0.19 0.15 1/345 2864
>
> T: 0 ( 2864) P:80 I:10000 C: 10000 Min: 4 Act: 69 Avg: 46
> Max: 119
> policy: fifo: loadavg: 0.39 0.28 0.19 1/346 2869
>
> T: 0 ( 2867) P:80 I:10000 C: 10000 Min: 3 Act: 14 Avg: 27
> Max: 361
> policy: fifo: loadavg: 0.10 0.20 0.17 1/347 2875
>
> T: 0 ( 2872) P:80 I:10000 C: 10000 Min: 4 Act: 14 Avg: 31
> Max: 425
> policy: fifo: loadavg: 0.01 0.13 0.15 1/346 2882
>
> T: 0 ( 2879) P:80 I:10000 C: 10000 Min: 4 Act: 58 Avg: 55
> Max: 186
> policy: fifo: loadavg: 0.09 0.12 0.13 1/346 2887
>
> T: 0 ( 2885) P:80 I:10000 C: 10000 Min: 4 Act: 67 Avg: 50
> Max: 129
> policy: fifo: loadavg: 0.10 0.12 0.13 1/347 2890
>
> ----------------------------------------------------------------------
> 2.6.39.1-1.threadirqs.1.fc14.ccrma.i686.PAE
> ----------------------------------------------------------------------
>
> $ while true ; do ./cyclictest -t1 -p 80 -n -i 10000 -l 10000 ;
> sleep 10; done
> policy: fifo: loadavg: 0.13 0.25 0.12 1/290 2279
>
> T: 0 ( 2279) P:80 I:10000 C: 10000 Min: 5 Act: 42 Avg: 45
> Max: 1015
> policy: fifo: loadavg: 0.64 0.36 0.18 1/338 2567
>
> T: 0 ( 2299) P:80 I:10000 C: 10000 Min: 4 Act: 48 Avg: 44
> Max: 3124
> policy: fifo: loadavg: 0.20 0.30 0.18 1/337 2583
>
> T: 0 ( 2571) P:80 I:10000 C: 10000 Min: 3 Act: 43 Avg: 50
> Max: 10301
> policy: fifo: loadavg: 0.07 0.22 0.16 2/341 2592
>
> T: 0 ( 2586) P:80 I:10000 C: 10000 Min: 5 Act: 30 Avg: 46
> Max: 15227
> policy: fifo: loadavg: 0.48 0.33 0.21 3/340 2602
>
> T: 0 ( 2595) P:80 I:10000 C: 10000 Min: 4 Act: 7 Avg: 29
> Max: 992
> policy: fifo: loadavg: 0.17 0.28 0.21 1/340 2613
>
> T: 0 ( 2610) P:80 I:10000 C: 10000 Min: 3 Act: 15 Avg: 32
> Max: 99
> policy: fifo: loadavg: 0.34 0.27 0.21 4/346 2660
>
> T: 0 ( 2616) P:80 I:10000 C: 10000 Min: 3 Act: 14 Avg: 36
> Max: 1326
> policy: fifo: loadavg: 0.14 0.25 0.22 2/342 2680
>
> T: 0 ( 2665) P:80 I:10000 C: 10000 Min: 3 Act: 14 Avg: 38
> Max: 709
> policy: fifo: loadavg: 0.18 0.24 0.22 1/342 2687
>
> T: 0 ( 2683) P:80 I:10000 C: 10000 Min: 4 Act: 17 Avg: 44
> Max: 17692
> policy: fifo: loadavg: 0.15 0.23 0.22 1/343 2690
>
> ----------------------------------------------------------------------
> 2.6.34.8-68.rt0.3.fc13.ccrma.i686.rtPAE
> ----------------------------------------------------------------------
>
> while true ; do ./cyclictest -t1 -p 80 -n -i 10000 -l 10000 ; sleep 10; done
> policy: fifo: loadavg: 0.19 0.30 0.13 1/355 2561
>
> T: 0 ( 2542) P:80 I:10000 C: 10000 Min: 3 Act: 27 Avg: 33
> Max: 143
> policy: fifo: loadavg: 0.03 0.20 0.11 1/354 2565
>
> T: 0 ( 2564) P:80 I:10000 C: 10000 Min: 6 Act: 15 Avg: 55
> Max: 135
> policy: fifo: loadavg: 0.53 0.27 0.14 3/401 2780
>
> T: 0 ( 2568) P:80 I:10000 C: 10000 Min: 3 Act: 9 Avg: 21
> Max: 134
> policy: fifo: loadavg: 0.50 0.39 0.20 1/405 2899
>
> T: 0 ( 2869) P:80 I:10000 C: 10000 Min: 3 Act: 66 Avg: 36
> Max: 119
> policy: fifo: loadavg: 0.13 0.28 0.18 1/404 2902
>
> T: 0 ( 2902) P:80 I:10000 C: 10000 Min: 3 Act: 48 Avg: 31
> Max: 116
> policy: fifo: loadavg: 0.10 0.27 0.17 1/405 2905
>
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-- 
Aurélien
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