Real time for Ubuntu Studio 10.04 amd64
Ralf Mardorf
ralf.mardorf at alice-dsl.net
Mon Jul 12 11:30:54 BST 2010
Hi Ken :)
On Sun, 2010-07-11 at 23:02 -0500, Kenneth Koym wrote:
> Ralf, Keep making these type postings; we need your expertise and
> questions! Ken
>
> On Sun, Jul 11, 2010 at 8:29 PM, Ralf Mardorf
> <ralf.mardorf at alice-dsl.net> wrote:
> Hi :)
>
> I'm new to the list. Regarding to hw MIDI jitter, I'm testing
> and
> comparing several Linux setups.
>
> Here is a rough summary of my latest thread on LAD.
What's bad with this posting? This is my question:
> I wonder what I need to do, to get a kernel-rt for
> Ubuntustudio 10.04?
In other words, I couldn't boot a kernel-rt, but to do real time audio
work, I need a kernel-rt. My question is about hints, what might be
going wrong and how to solve it.
Here are some details about my machine:
Mobo M2A-VM HDMI
AMD Athlon(tm) X2 Dual Core Processor BE-2350
RAM 2 GB
Graphics NVIDIA 7200 GS
Sound cards 2x Terratec EWX 24/96
This is the reason why I need a kernel-rt:
> ........................................................................
> Ubuntu Studio 10.04 amd64
> $ uname -a
> Linux ubuntu 2.6.32-23-preempt #37-Ubuntu SMP PREEMPT Fri Jun
> 11
> 10:19:07 UTC 2010 x86_64 GNU/Linux
>
> $ alsa-midi-latency-test -Rrw=2 -o20:0 -i20:0
> > alsa-midi-latency-test 0.0.3
> > set_realtime_priority(SCHED_FIFO, 99).. done.
> > clock resolution: 0.000000001 s
> > SUCCESS
>
> best latency was 1.00 ms
> worst latency was 3.36 ms, which is great.
>
> 3.36 ms isn't great, but unusable to make music.
>
> ........................................................................
> openSUSE 11.2 amd64
> > uname -a
> Linux suse11-2 2.6.31.6-rt19 #1 SMP PREEMPT RT Wed Nov 18
> 16:59:26 CET
> 2009 x86_64 x86_64 x86_64 GNU/Linux
>
> > alsa-midi-latency-test -Rrw=2 -o16:0 -i16:0
> > alsa-midi-latency-test 0.0.3
> > set_realtime_priority(SCHED_FIFO, 99).. done.
> > clock resolution: 0.000000001 s
> > SUCCESS
>
> best latency was 0.99 ms
> worst latency was 1.05 ms, which is great.
>
> ........................................................................
>
> PREEMPT vs PREEMPT RT and of course frequency scaling for an
> audio
> distro should be at performance by default, anyway, the
> frequency
> scaling isn't a big deal.
This is about the issues when I try to boot the kernel-rt from the
repositories resp. the messages I get instead of a desktop session:
> I tried to boot the kernel-rt from the Ubuntu repositories and
> I tried
> to build a kernel-rt myself.
>
> If I try to boot kernel 2.6.31-11-rt or kernel 2.6.31-10-rt
> from the
> repositories I get
> 'mount: mounting none on /dev failed: No such device.'
> Regading to the
> web this might be, because of CONFIG_DEVTMPFS.
>
> # cat config-2.6.31-11-rt | grep CONFIG_DEVTMPFS
> # cat config-2.6.32-23-preempt | grep CONFIG_DEVTMPFS
> CONFIG_DEVTMPFS=y
> CONFIG_DEVTMPFS_MOUNT=y
>
> When I try to boot kernel 2.6.33-23-realtime from the
> repository I get
> 'ACPI: Expecting a [Reference] package element, found type 0'.
I also tried to build a kernel-rt without succes:
> At least this three kernel-rt from the repositories come with
> an initrd.
> The kernel I tried to build the way I usually build kernels
> for Ubuntu
> with success, is missing an initrd.
>
> $ cd /usr/src
> $ sudo synaptic
> I checked if those packages were installed:
> bin86
> build-essential
> bzip2
> fakeroot
> gcc
> kernel-package
> make
> libncurses5-dev
> $ wget
> ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.33.5.tar.bz2
> $ wget
> http://www.kernel.org/pub/linux/kernel/projects/rt/patch-2.6.33.5-rt23.bz2
> $ tar xvjf linux-2.6.33.5.tar.bz2
> $ rm linux-2.6.33.5.tar.bz2
> $ mv linux-2.6.33.5 linux-2.6.33.5-rt23
> $ ln -s linux-2.6.33.5-rt23 linux
> $ cd linux
> $ bunzip2 ../patch-2.6.33.5-rt23.bz2
> $ patch -p1 < ../patch-2.6.33.5-rt23
> $ rm ../patch-2.6.33.5-rt23
> $ cp /boot/config-2.6.32-23-preempt .config
> $ make oldconfig
> 81 x Enter
> $ make menuconfig
> Edited from Generic-x86-64 to Opteron/Athlon64/Hammer/K8
> Save an Alternate Configuration File
> $ make oldconfig
> Nothing to do
> $ make-kpkg clean
> $ export CONCURRENCY_LEVEL=2
> This didn't work:
> $ make-kpkg --rootcmd fakeroot --initrd kernel-image
> kernel-headers
> kernel-source
> 50 minutes later
> make[5]: ***
> [drivers/staging/comedi/drivers/quatech_daqp_cs.o]
> Error 1
> make[4]: *** [drivers/staging/comedi/drivers] Error 2
> Hence I edited .config:
> $ cat .config | grep COMEDI
> CONFIG_COMEDI=m
> # CONFIG_COMEDI_DEBUG is not set
> CONFIG_COMEDI_PCI_DRIVERS=m
> CONFIG_COMEDI_PCMCIA_DRIVERS=m
> CONFIG_COMEDI_USB_DRIVERS=m
> $ gedit .config
> $ cat .config | grep COMEDI
> # CONFIG_COMEDI is not set
> # CONFIG_COMEDI_DEBUG is not set
> # CONFIG_COMEDI_PCI_DRIVERS is not set
> # CONFIG_COMEDI_PCMCIA_DRIVERS is not set
> # CONFIG_COMEDI_USB_DRIVERS is not set
> $ make oldconfig
> Nothing to do
> $ make-kpkg clean
> $ make-kpkg --rootcmd fakeroot --initrd kernel-image
> kernel-headers
> kernel-source
> Another 50 minutes later
> make[4]: *** [drivers/staging/pohmelfs/inode.o] Error 1
> make[3]: *** [drivers/staging/pohmelfs] Error 2
> Hence I edited .config:
> $ cat .config | grep POHMEL
> CONFIG_POHMELFS=m
> # CONFIG_POHMELFS_DEBUG is not set
> CONFIG_POHMELFS_CRYPTO=y
> $ gedit .config
> $ cat .config | grep POHMEL
> # CONFIG_POHMELFS is not set
> # CONFIG_POHMELFS_DEBUG is not set
> # CONFIG_POHMELFS_CRYPTO is not set
> $ make oldconfig
> Nothing to do
> $ make-kpkg clean
> Here it is ok:
> $ make-kpkg --rootcmd fakeroot --initrd kernel-image
> kernel-headers
> kernel-source
> 80 minutes later
> $ cd ..
> $ sudo dpkg -i
> linux-image-2.6.33.5-rt23_2.6.33.5-rt23-10.00.Custom_amd64.deb
>
> ........................................................................
>
> When I tried to boot the kernel I got
>
> '[ 0.499322] ACPI: Expecting a [Reference] package element,
> found
> type 0
> [ 0.811991] kernel panic - not syncing: VPS: Unable to
> mount root fs
> on unknown-block (0,0)'
Here I was asking again for hints:
> Any hints are welcome!
>
> Cheers!
>
> Ralf
Help still is wanted. And I can't see what's bad about my request.
Cheers!
Ralf
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