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Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

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Low Latency(?) Kernel for OpenSuse 11.1

From: "andrew cooke" <andrew@...>

Date: Fri, 30 Jan 2009 21:11:39 -0300 (CLST)

I did the following to compile a low latency kernel for Opensuse 11.1.  In
truth I don't fully understand the options, so I may not have chose things
correctly.  In any case, my audio playback still has intermittent hiccups,
so I will return to the default kernel (since it's simpler to maintain).

But in case it's helpful for anyone else, this is what I did.  Basically
just install the kernel source and follow the instructions in the README -
/usr/share/doc/packages/kernel-source/README.SUSE.  This link is also
useful -
http://en.opensuse.org/Configure%2C_Build_and_Install_a_Custom_Linux_Kernel

- Check that current system is up-to-date via Yast (all
  packages; update if newer version available)

- Install the kernel-source package

- Make a copy of boot/grub/menu.lst

- Note info from boot.msg:
  root=/dev/md3 resume=/dev/md5 splash=silent showopts vga=0x31a

- Note the location of /boot:
  Device: /dev/sdd1
  Device Path: pci-0000:00:1f.2-scsi-0:0:1:0-part1
  Device ID 1: ata-WDC_WD3200JS-60PDB0_WD-WCAPD2606109-part1
  Device ID 2: scsi-SATA_WDC_WD3200JS-60_WD-WCAPD2606109-part1

- Read .boot/boot.readme and noted:
p6 boot: cat /boot/grub/device.map
(hd1)   /dev/disk/by-id/ata-WDC_WD3200JS-60PDB0_WD-WCAPD2606109
(hd5)   /dev/disk/by-id/scsi-SFUJITSU_MAN3184MP_UFS0P1900J1C
(hd0)   /dev/disk/by-id/ata-WDC_WD3200JS-60PDB0_WD-WCAPD2611078
(hd3)   /dev/disk/by-id/ata-WDC_WD3200JS-60PDB0_WD-WCAPD2661401
(hd4)   /dev/disk/by-id/scsi-SFUJITSU_MAN3184MP_UFS0P1900D0N
(hd2)   /dev/disk/by-id/ata-WDC_WD3200JS-60PDB0_WD-WCAPD2606397
qp6 boot: cat /etc/grub.conf
setup --stage2=/boot/grub/stage2 --force-lba (hd0) (hd1,0)
quit

- It's not clear to me where the boot loader is installed.
  The Yast boot loader config gives MBR as the boot loader
  location defeault.

- Read /usr/share/doc/packages/kernel-source/README.SUSE

- cd /usr/src/linux

- make cloneconfig

- more Makefile; make help

- make xconfig
  (failed; install qt3-devel; retry)
  Disable dynamic ticks
  Select correct processor family
  Select preemptible kernel
  Set time frequency to 1000Hz
  Can see no way to set localversion.

- make menuconfig
  Set Local version

- make
  make modules_install
  make install

- egrep allow_unsupported_modules /etc/modprobe.d/unsupported-modules
  (shows 1)

- check /boot/grub/menu.lst
  check /boot

- reboot

- no X11

- init 3
  cd /usr/share/doc
  mkdir nvidia
  cd nvidia
  wget
http://us.download.nvidia.com/XFree86/Linux-x86_64/180.22/NVIDIA-Linux-x8\
6_64-180.22-pkg2.run
  chmod +x NVIDIA-Linux-x86_64-180.22-pkg2.run
  ./NVIDIA-Linux-x86_64-180.22-pkg2.run

- reboot

Andrew

Only Early Kernels

From: "andrew cooke" <andrew@...>

Date: Tue, 30 Jun 2009 19:10:12 -0400 (CLT)

I should add (since this page gets occasional readers) that this was only
a problem with early kernels in OpenSuse 11.1.  If you update via Yast
then you should get a kernel with no latency issues (ie it plays back
music just fine).

Andrew

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