This sounded interesting, so I googled for some benchmark test to measure differences. I found nbench, which measures performance by executing some typical algorithms and compares them to a Pentium 90 based system. So I installed it and run on the i586 CHOST system, then rebuild it completely to i486 CHOST and run it again. The differences are not that huge, but on some algorithms they’re measurable:

The first 13 bars are the different algorithms. The main difference is on the string sort, which is heavily memory dependent. That last 3 rows are a index based on the algorithms. Here is main difference on memory index, as the normalized version shows very clear (positive values mean that i486 is faster):

As there is no significant disadvantage of the i486 CHOST, this seems to be the choice.

If anybody has other (free) benchmarks to suggest, please let me know.

Sadly there is no ebuild for flashrom in portage, so Gentoo users (and maybe some other) have to build it on there own, but it’s quite easy. You need to install subversion, an open-source revision control system, first:

emerge -va subversion

As there is no portage package for flashrom, we need to install it somewhere. I installed it in /root/flashrom so it can be removed easily. You can achieve this by

cd root
svn co svn://coreboot.org/flashrom/trunk flashrom
cd flashrom
make

You can do an optional

make install

to install the binaries in /usr/local/sbin and install the man page. Now we should save our old BIOS. Running

flashrom -r /root/bios_save.bin

should display some info on the found chipset and flash chip:

Calibrating delay loop... OK.
No coreboot table found.
Found chipset "AMD CS5536", enabling flash write... OK.
Found chip "AMIC A49LF040A" (512 KB) at physical address 0xfff80000.
Reading flash... done.

If you have an image of the old installed BIOS you can check, if everything went right, by

diff /root/bios_save.bin /root/bios_old.bin

where /root/bios_old.bin is the old BIOS version, preferable found on the manufacturer’s website. Now we can update the BIOS. Download the new BIOS version (ALIX.3D3 can be found here) and run:

flashrom -wv /root/bios_new.bin

flashrom should print some information, a process status and after all a VERIFIED, if everything went right:

Calibrating delay loop... OK.
No coreboot table found.
Found chipset "AMD CS5536", enabling flash write... OK.
Found chip "AMIC A49LF040A" (512 KB) at physical address 0xfff80000.
Flash image seems to be a legacy BIOS. Disabling checks.
Programming page: 0007 at address: 0x00070000
Verifying flash... VERIFIED.

Now your BIOS should be updated. It’s time to plug (power) and pray.

Update: After writing a Gentoo Bug report, there is now an ebuild in portage. You can install it by

emerge -va flashrom

Here comes bonding (sometimes called (port) trunking or link aggregation) to play. It connects two ore more ethernet ports to one virtual port with only one MAC and so mostly one IP address. Wheres earlier only two hosts (with the same OS running) or two switches (from the same vendor) could be connected, nowadays there’s a standard protocol which makes it easy: LACP which is part of IEEE 802.3ad. Linux supports difference bonding mechanisms including 802.3ad. To enable bonding at all there are some kernel settings needed:

Device Drivers  --->
[*] Network device support  --->
<*>   Bonding driver support

After compiling and rebooting, we need a userspace tool for configuring the virtual interface. It’s called ifenslave and provided with the Linux kernel. You can either compile it by hand

/usr/src/linux/Documentation/networking
gcc -Wall -O -I/usr/src/linux/include ifenslave.c -o ifenslave
cp ifenslave /sbin/ifenslave

or install it by emerge if you run Gentoo Linux:

emerge -va ifenslave

Now we can configure the bonding device, called bond0. Firstofall we need to set the 802.3ad mode and the MII link monitoring frequency by

echo "802.3ad" > /sys/class/net/bond0/bonding/mode
echo 100 >/sys/class/net/bond0/bonding/miimon

Now we can up the device and add some ethernet ports:

ifconfig bond0 up
ifenslave bond0 eth0
ifenslave bond0 eth1

Now bond0 is ready to be used. Run a dhcp client or set an IP by

ifconfig bond0 192.168.1.2 netmask 255.255.255.0

These steps are needed on each reboot. If you’re running gentoo, you can use baselayout for this. Add

config_eth0=( "none" )
config_eth1=( "none" )
preup() {
	# Adjusting the bonding mode / MII monitor
	# Possible modes are : 0, 1, 2, 3, 4, 5, 6,
	#     OR
	#   balance-rr, active-backup, balance-xor, broadcast,
	#   802.3ad, balance-tlb, balance-alb
	# MII monitor time interval typically: 100 milliseconds
	if [[ ${IFACE} == "bond0" ]] ; then
		BOND_MODE="802.3ad"
		BOND_MIIMON="100"
		echo ${BOND_MODE} >/sys/class/net/bond0/bonding/mode
		echo ${BOND_MIIMON}  >/sys/class/net/bond0/bonding/miimon
		einfo "Bonding mode is set to ${BOND_MODE} on ${IFACE}"
		einfo "MII monitor interval is set to ${BOND_MIIMON} ms on ${IFACE}"
	else
		einfo "Doing nothing on ${IFACE}"
	fi
	return 0
}
slaves_bond0="eth0 eth1"
config_bond0=( "dhcp" )

to your /etc/conf.d/net. I found this nice preup part in the Gentoo Wiki Archive.

Now you have to configure the other side of the link. You can either use a Linux box and configure it the same way or a 802.3ad-capable switch. I used an HP Procurve 1800-24G switch. You have to enable LACP on the ports you’re connected:

HP Procurve 1800-24G LACP Configuration

Now everything should work and you can enjoy a 2 GBits (or more) link. Further details can be found in the kernel documentation.

First of all, I recommend installing Gentoo on a normal desktop to get to know the installing process, which is a bit different from graphical installers of mainstream distros. The Gentoo Handbook is a great documentation how this done.

To install gentoo, you have to boot a minimal or “rescue” linux usually from cd/dvd. I tried to convice the bios to boot from a usb cd-rom drive, but I hadn’t any success.

So I had to prepare a USB stick to boot from. There’s a nice tool UNetbootin which automatically copies ISO images to a usbstick and makes it bootable. I tried a lot with the Linux version of it but didn’t had any success regardless of which ISO image or USB stick I took. So I booted windows and tried it with this version. I had success on the first attempt, using the install-x86-minimal.iso from Gentoo and a 3 EUR SD-card Reader with a 4 GB SDHC card in it, formatted as FAT32 as the only partition (not in superfloppy mode).

If you’ve got a booting usb stick, insert it into a USB plug of the board, attach a USB keyboard and a monitor to the VGA port. Power on and press escape to select the boot menu. There should be an option for the usb stick if everything went fine.

Now the gentoo minimal system should boot and you can proceed with the usual installing (look into Gentoo Handbook for details). The AMD Geode LX800 cpu is a i586 cpu, so you have to install a i386, i486 oder i586 stage (i686 or amd64 won’t work!). I installed a i486 stage 3 and updated later to i586.

Partitioning should follow your preferences but don’t a forget a swap partition. 256 MB of RAM is not that much and gcc will not compile without!

I took

CFLAGS="-O2 -march=i486 -pipe"

for installation as the gcc version on the stage3 archive don’t support the geode march.

The rest of the installation is business as usual. I installed gentoo-sources for a optimized kernel and took this configuration here: ALIX.3D3 kernel-2.6.29-r2 config

After finishing installation and booting with the new kernel, it’s time to update the systems to i586. For this, at first update all packages to actual version, especially gcc to version 4.3. Afterwards it’s save to change

CFLAGS="-march=geode -Os -fno-align-jumps -fno-align-functions -fno-align-labels -fno-align-loops -pipe -fomit-frame-pointer"

and proceed with changing of the CHOST variable. There’s a nice tutorial here: Changing CHOST.

Now you should have a nice and optimized gentoo on your ALIX.3D3

In earlier times I used a commented bash script to setup the rules after booting, but using Gentoo nowadays there is a nice init script saving and restoring my tables. Using this I stopped commenting the firewall rules, but yesterday I found a very nice solution for this problem.

Iptables has a special “match” for comments. You have to enable it in your kernel config like

  [*] Networking support  --->
     Networking options
        [*] Network packet filtering framework (Netfilter)  --->
           Core Netfilter Configuration  --->
              -*- Netfilter Xtables support (required for ip_tables)
              <*>   "comment" match support

or as a module.

Then you’re able to add rules like

iptables -A INPUT -m state --state RELATED,ESTABLISHED \
  -m comment --comment "allow all established connections" -j ACCEPT

And if you list your rules you get something like

Chain INPUT (policy DROP)
target  prot opt source     destination
ACCEPT  all  --  anywhere   anywhere   state RELATED,ESTABLISHED
                                       /* allow all established connections */

It’s a pity that I never saw this in any iptables tutorials.

To get KMS running on my macbook, I installed the 2.6.29 with the following settings

  Device Drivers  --->
    Graphics support  --->
      <*> Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)  --->
        <*>   Intel 830M, 845G, 852GM, 855GM, 865G (i915 driver)  --->
          i915 driver
          [ ]    Enable modesetting on intel by default

You don’t have to enable KMS by default. It’s possible to do this via i915.modeset=1 as a boot option.

After booting the kernel, drm should have detected your outputs and load inteldrmfb

[    1.905481] [drm] TV-15: set mode NTSC 480i 0
[    2.021462] allocated 1280x800 fb: 0x00fdf000, bo ffff88013eaf2900
[    2.094941] [drm] LVDS-8: set mode 1280x800 17
[    2.191879] Console: switching to colour frame buffer device 160x50
[    2.195013] fb0: inteldrmfb frame buffer device
[    2.195038] registered panic notifier
[    2.195059] [drm] Initialized i915 1.6.0 20080730 on minor 0

To use KMS within X11, I had to update the latest xorg-server, x11-libs and xf86-video-intel from the x11-overlay. In /etc/X11/xorgs.conf must

        Option          "AccelMethod"   "UXA"

set in the intel driver section.

Notice that output names may have changed, if you use a multimonitor setup oder xrandr. I had VGA,TV,LVDS,TMDS-1 prior to 2.6.29 and now it’s VGA1,TV1,LVDS1,DVI1.

Das Programm AICCU initialisiert die Tunnel und benötigt als Konfiguration lediglich SiXXs-Benutzername und Passwort sowie eine Tunnel Nummer. Das Programm gibt es als net-misc/aiccu als Ebuild für Gentoo.

Ist der Tunnel erfolgreich eingerichtet kann auch ein IPv6 Subnet beantragt werden und weitere PCs im Heimnetz ans IPv6 Netz zu bekommen. Der Gentoo-IPv6-Router-Guide erklärt wie man radvd und dhcpv6 konfiguriert.