Re: [proaudio] Setting up realtime

["Arve Barsnes" <arve.barsnes@xxxxxxxxx>]

Finally had time to sit down and compile this thing and restart.
/proc/timer_list seems a little weird, but then I'm not totally sure
what it's supposed to look like. For each CPU I get two different
clocks at the top, and I'm not 100% on how to interpret it:

cpu: 0
 clock 0:
  .index:      0
  .resolution: 1 nsecs
  .get_time:   ktime_get_real
  .offset:     1213407705376864661 nsecs
active timers:
 clock 1:
  .index:      1
  .resolution: 1 nsecs
  .get_time:   ktime_get
  .offset:     0 nsecs

In addition I seem to have 5 tick devices, the last 4 of which seems
set up good with the hrtimer_interrupt event handler, but the first
one looks totally different:

Tick Device: mode:     1
Clock Event Device: pit
 max_delta_ns:   27461866
 min_delta_ns:   12571
 mult:           5124677
 shift:          32
 mode:           3
 next_event:     9223372036854775807 nsecs
 set_next_event: pit_next_event
 set_mode:       init_pit_timer
 event_handler:  tick_handle_oneshot_broadcast
tick_broadcast_mask: 00000000
tick_broadcast_oneshot_mask: 00000000

So, anyone tried the cyclictest tool? This is where I get really
confused, since it is supposed to give me an average of how much
latency there is in the system, but the results I get are negative
numbers!

# ./cyclictest -n -p 80 -i 500 -l 5000
0.08 0.63 0.70 1/193 11347

T: 0 (11347) P:80 I:500 C:   5000 Min:   -696 Act: -668 Avg: -681 Max:    -666

All this has been like this since before the recompile though, so all
this might not matter. Off to test it now!

On Mon, Jun 9, 2008 at 3:03 PM, Mysth-R <mysthr21@xxxxxxxxx> wrote:
> Hi,
>
> I Tried to compile a new kernel all the week end, and now I got it ! Here is
> what to do to compile a 2.6.25.4-rt5 kernel :
>
> $ su -
> # cd /usr/src
> # wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.25.4.tar.gz
> //get the 2.6.25.4 kernel
> # wget http://rt.et.redhat.com/download/older/patch-2.6.25.4-rt5.bz2  // get
> the RT patch for this kernel
>
> Uncompress these to files. then :
>
> # mv linux-2.6.25.4 linux-2.6.25.4-rt5
> # rm linux                                          //to remove any symlink
> # ln -s linux-2.6.25.4-rt5 linux                    // to create a new
> symlink.
> # cd linux                                            // You will work in
> this directory linked to your linux-2.6.25.4-rt5 directory.
> # patch -p1 < ../patch-2.6.25.4-rt5       // apply the patch to make your
> new kernel RT
>
>
> Perhaps there is others patches ?  but this is the most important to use RT.
> (If anyone could tells us if there is others patches ?..)
>
> # make clean        // not necessary the first time, but necessary you want
> to compile another time
> # zcat /proc/config.gz > .config         // to get your current kernel
> .config
> # make oldconfig
>
> Then you can configure your kernel according to your needs.
>
> # make menuconfig
> # make && make modules_install
> # cp arch/i386/boot/bzImage /boot/kernel-2.6.25.4-rt5
> # cp System.map /boot/System.map-2.6.25.4-rt5
>
> Then edit your /boot/grub/menu/lst
>
>
> This is the way to compile your kernel.
> Now as Christian tolds you there is some option you must activate to get
> really good performances.
> You can desactivate all options you do not needs (scsi, pcmcia, etc...)
>
> good luck
>
>
>
>
>
> 2008/6/9 Arve Barsnes <arve.barsnes@xxxxxxxxx>:
>>
>> Nevermind, found it. Will recompile and try it when I get home.
>>
>> On Mon, Jun 9, 2008 at 7:04 AM, Arve Barsnes <arve.barsnes@xxxxxxxxx>
>> wrote:
>> > Okay,  I had group scheduling activated, and a grep of my config shows
>> > CFQ as not being the default IO scheduler. Couldn't find the setting
>> > in menuconfig right now so I'll have to check more when I get back
>> > home from work. Thanks for the tips though.
>> >
>> > On Mon, Jun 9, 2008 at 12:42 AM, Christian <krampenschiesser@xxxxxxxxxx>
>> > wrote:
>> >> -----BEGIN PGP SIGNED MESSAGE-----
>> >> Hash: SHA1
>> >>
>> >> Arve Barsnes schrieb:
>> >> | Can anyone give a summary of the current method of setting up
>> >> | realtime? jack is now saying latency is below 1 ms, but it's giving
>> >> me
>> >> | an enormous amount of xruns. I'm guessing my kernel isn't completely
>> >> | correctly set up, and I can't really find any good guides, only vague
>> >> | hints to add those features, but not those, and whatever you do don't
>> >> | use this. Might be because the kernels change so much between
>> >> | versions.
>> >> |
>> >> | I've set up pam, configured kernel, done jack config in qjackctl and
>> >> | set up my .asoundrc by this page: http://gentoo-wiki.com/HOWTO_Jack
>> >> |
>> >> | A more specific kernel setup would be welcome, for any kernel you'd
>> >> | like, I can change versions to fit whatever is easier to explain,
>> >> | currently running 2.6.24-rt1 from the overlay. Also having
>> >> | 2.6.25.4-rt1 that was posted on this list a while back, but I don't
>> >> | know if it is currently configured to run at all. Anything else I
>> >> need
>> >> | to do would also be welcome with a good explanation. I've been using
>> >> | Debian for a few years now, so consider me a n00b to Gentoo, although
>> >> | I used it a few years ago. :)
>> >> |
>> >> | Hope to hear something soon :)
>> >> |
>> >> | Regards,
>> >> | Arve
>> >> |
>> >> |
>> >> |
>> >> |
>> >> Deactived group scheduling
>> >> Use CFQ as default IO scheduler.
>> >> High Res timer support.
>> >> Complete Preemption(Real-Time-Patch)
>> >> 1000hz timer frequency.
>> >>
>> >> This does my job.
>> >> -----BEGIN PGP SIGNATURE-----
>> >> Version: GnuPG v2.0.9 (GNU/Linux)
>> >> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
>> >>
>> >> iEYEARECAAYFAkhMYHEACgkQVC26eJ+o0+0ZFgCghfs1vcQmQoXagLxVVTIPTFAz
>> >> SjAAn18kfckn45gg7YU7+/3I0ABI3uI+
>> >> =39J8
>> >> -----END PGP SIGNATURE-----
>> >>
>> >>
>> >>
>> >
>>
>>
>
>
>
> --
> *
> ***************************************************************************************
> * {^_^} Mysth-R {^_^}
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