Mathias Krause wrote: >> And because of the sources, I run Synaptic and saw that there aren't the >> common headers in the amd64 repository. In any case I guess it is good >> to compile the latest kernel and to add latest rtirq, when there's the >> need to build the graphics module ... not generally, but at the moment >> there seems to be a big step for the real-time kernel (and rtirq). >> > > That's an important thing i did not yet understand. What is the difference > between the kernel-multimedia-amd64 and rt19-20100103? When looking at the > naming of that kernels, the last one seems that rt19 has nothing todo with > multimedia ... and the rt kernel seems to be to be more a snapshot, then a > tested version.... (and remember, i got that rt19 kernel from a privat > repository, not from the official one...) >
There is the basic kernel, called vanilla kernel, it has got a major number, e.g. 2.6.31 and a minor number e.g. .6. You can get the source for 2.6.31 and a patch .6 separated or the complete source 2.6.31.6. For real-time you need an additional patch, e.g. -rt19. The complete name than will be 2.6.31.6-rt19. Older patches are available here: http://www.kernel.org/pub/linux/kernel/projects/rt/older/ I build a kernel 2.6.31.6-rt19 for my 64 Studio. The patch needs to be especially for the kernel version. The actual one is patch-2.6.31.12-rt20, this means patch -rt20 is the micro number and the patch is only for kernel 2.6.31.12, available at http://www.kernel.org/pub/linux/kernel/projects/rt/. Today it's common only to use this rt patches and I'm nearly sure the 64 Studio guys are using it too. In the past there were 2 different patches common. Anyway, even similar kernel versions, using the same patch could have different configurations. spinymouse-s...@64studio:~/Desktop$ ls /boot/config* /boot/config-2.6.29-1-multimedia-amd64 /boot/config-2.6.29.3-rt13-suspend2 /boot/config-2.6.31.5-rt18 /boot/config-2.6.31.6-rt19 I could build a new kernel 2.6.31.6-rt19, but with another configuration and call it e.g. 2.6.31.6-rt19-2010Feb06. For example, there is a snd-hrtimer module, that did exist for 2.6.29 kernels and it exists also for 2.6.31 kernels. The multimedia kernel isn't configured with it. spinymouse-s...@64studio:~/Desktop$ cat /boot/config-2.6.29-1-multimedia-amd64 | grep CONFIG_SND_HRTIMER # CONFIG_SND_HRTIMER is not set spinymouse-s...@64studio:~/Desktop$ cat /boot/config-2.6.31.6-rt19 | grep CONFIG_SND_HRTIMER CONFIG_SND_HRTIMER=m spinymouse-s...@64studio:~/Desktop$ You also could build a kernel 2.6.29-1-multimedia-amd64 with, resp. a kernel 2.6.31.6-rt19 without this option. Even if SND_HRTIMER is more experimental than the real-time patch already is, you don't need to load and use the module, so it doesn't have impact to the stability of the kernel. But for example the number of CPUs could have impact. spinymouse-s...@64studio:~/Desktop$ cat /boot/config-2.6.29-1-multimedia-amd64 | grep CONFIG_NR_CPUS CONFIG_NR_CPUS=512 spinymouse-s...@64studio:~/Desktop$ cat /boot/config-2.6.31.6-rt19 | grep CONFIG_NR_CPUS CONFIG_NR_CPUS=2 While CONFIG_NR_CPUS is set up to 512, there shouldn't be trouble, when using a quad-core CPU, but when the value is 2, I guess there could be trouble. A new kernel and a new rt patch are less proved than older once, but the new once are the latest releases and they aren't just snapshots for testing only. Differences will be because of different kernel versions and because of the configuration, but for same kernel versions differences aren't because of snapshot developer directory versions, but only because of configurations, or because there are additional patches, e.g. because of an additional patch for a special kind of suspend function. For the distro there could be dependencies too, e.g. if you'll use a kernel 2.6.31.6-rt instead of a kernel 2.6.29-1-multimedia = 2.6.29.x-rt, you also need latest rtirq script, because of changes for setting up preemtion/real-time values. You need to ask Quentin about possible "special configurations" or additional patches, but I'm sure his kernel is a preemtion/real-time kernel and I'm nearly sure that the multimedia kernel don't comes with additional patches, but the regular rt patch. _______________________________________________ 64studio-users mailing list [email protected] http://lists.64studio.com/mailman/listinfo/64studio-users
