Re: Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.31-7

[Rui Nuno Capela]

Ingo Molnar wrote:
>
> * Ingo Molnar <mingo@xxxxxxx> wrote:
>
>> but please try to the -31-10 kernel that i've just uploaded, it has a
>> number of tracer enhancements:
>
> make that -31-13 (or later). Earlier kernels had a bug in where the
> process name tracking only worked for the first latency trace saved,
> subsequent traces showed 'unknown' for the process name. In -13 i've
> also added a printk that shows the latest user latency in a one-line
> printk - just like the built-in latency tracing modes do:
>
>  (gettimeofday/3671/CPU#0): new 3068 us user-latency.
>  (gettimeofday/3784/CPU#0): new 1008627 us user-latency.
>
> (this should also make it easier for helper scripts to save the traces,
> whenever they happen.)
>

OK.

I did my homework and managed to grab some latency traces for you to take
a look and see if it's alright. Please.

On attach you may find the files:

    xruntrace1.1.tar.gz
        - scripts used to arm and capture the latency traces;

    jack-0.99.14.0xruntrace-alsa.patch.gz
        - the actual patch applied to jack for trace auto-triggering;

    config-2.6.10-rc2-mm3-RT-V0.7.31-13.gz
        - the running kernel configuration, as taken from /proc/config.gz

    xruntrace1-2.6.10-rc2-mm3-RT-V0.7.31-13-*.trc.gz
        - the captured traces, as dumped with xruntrace1_watch.sh script.

    jack_test3.2.tar.gz
        - updated my jack_test3 benchmarking suite.


The traces were captured, while running a usual KDE desktop session (from
qjackctl) on my P4@xxxxxxx laptop (Mandrake 10.1):

    jackd -R -P60 -dalsa -dhw:0 -r44100 -p64 -n2 -S -P

Each trace shows only the first XRUN occurrence on a distinct jackd
session. Every other trace were triggered and captured after restarting
jackd.

Must say that XRUNs are rare but do occurr. Using the same jackd command
line, my jack_test3 suite is showing these figures by now:

    *********** CONSOLIDATED RESULTS ************
    Total seconds ran . . . . . . :  7200
    Number of clients . . . . . . :    16
    Ports per client  . . . . . . :     4
    *********************************************
    Summary Result Count  . . . . :     2 /     2
    *********************************************
    Timeout Rate  . . . . . . . . :(    0.0)/hour
    XRUN Rate . . . . . . . . . . :    13.8 /hour
    Delay Rate (>spare time)  . . :    13.8 /hour
    Delay Rate (>1000 usecs)  . . :     7.0 /hour
    Delay Maximum . . . . . . . . :  1022   usecs
    Cycle Maximum . . . . . . . . :  1048   usecs
    Average DSP Load. . . . . . . :    62.2 %
    Average CPU System Load . . . :    20.6 %
    Average CPU User Load . . . . :    48.5 %
    Average CPU Nice Load . . . . :     0.0 %
    Average CPU I/O Wait Load . . :     0.0 %
    Average CPU IRQ Load  . . . . :     0.0 %
    Average CPU Soft-IRQ Load . . :     0.0 %
    Average Interrupt Rate  . . . :  1689.2 /sec
    Average Context-Switch Rate . : 19778.2 /sec
    *********************************************

The IRQ process/threading priority status has been fixed as shown below:

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
    2 FF      90   - 130  0.0 S    IRQ 0
  728 FF      80   - 120  0.0 S<   IRQ 8
 2943 FF      70   - 110  0.0 S<   IRQ 5
 1500 FF      60   - 100  0.0 S<   IRQ 10
  841 FF      50   -  90  0.0 S<   IRQ 1
  736 FF      49   -  89  0.0 S<   IRQ 12
   20 FF      48   -  88  0.0 S<   IRQ 9
  814 FF      45   -  85  0.0 S<   IRQ 6
  821 FF      44   -  84  0.0 S<   IRQ 14
  823 FF      43   -  83  0.0 S<   IRQ 15
 2227 FF      40   -  80  0.0 S<   IRQ 11

# cat /proc/interrupts

           CPU0
  0:    6435186          XT-PIC  timer  0/35186
  1:       1164          XT-PIC  i8042  1/1164
  2:          0          XT-PIC  cascade  0/0
  5:         73          XT-PIC  ALI 5451  0/72
  8:          1          XT-PIC  rtc  0/1
  9:      20602          XT-PIC  acpi  0/20602
 10:          0          XT-PIC  ohci_hcd, ohci_hcd  0/0
 11:          5          XT-PIC  yenta  5/5
 12:      64317          XT-PIC  i8042  0/64317
 14:      11772          XT-PIC  ide0  0/11772
 15:         19          XT-PIC  ide1  0/19
NMI:          0
LOC:          0
ERR:          0
MIS:          0


Cheers.
-- 
rncbc aka Rui Nuno Capela
rncbc@xxxxxxxxx

Attachment: xruntrace1.1.tar.gz
Description: application/gzip-compressed

Attachment: jack-0.99.14.0xruntrace-alsa.patch.gz
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Attachment: config-2.6.10-rc2-mm3-RT-V0.7.31-13.gz
Description: application/gzip-compressed

Attachment: xruntrace1-2.6.10-rc2-mm3-RT-V0.7.31-13-20041129154425.trc.gz
Description: application/gzip-compressed

Attachment: xruntrace1-2.6.10-rc2-mm3-RT-V0.7.31-13-20041129184639.trc.gz
Description: application/gzip-compressed

Attachment: xruntrace1-2.6.10-rc2-mm3-RT-V0.7.31-13-20041129195721.trc.gz
Description: application/gzip-compressed

Attachment: jack_test3.2.tar.gz
Description: application/gzip-compressed