[CentOS] Kernel-utils stupidities (readahead and cpuspeed)

Wed Jul 12 10:46:38 UTC 2006
Johnny Hughes <mailing-lists at hughesjr.com>

On Mon, 2006-07-10 at 22:08 +0200, Simen Thoresen wrote:
> Hi all,
> I think I've spotted a few stupidities (bugs) in the current version of 
> kernel-utils (kernel-utils-2.4-13.1.80). I'm sure these are all propagated 
> from upstream, but I hope someone could have a quick look to verify this and 
> see if we either can push complaints upwards, or provide local fixes.
> The kernel-utils package provides several 'kernel-type' functions - 
> readahead and readahead_early and also the cpuspeed have a few problems;
> readahead 'reads ahead' (stats to copy to cache for speedy access?) the 
> files found in /etc/readahead.files. While most of these files are various 
> images and common binaries, some are libraries which have been replaced by 
> newer versions, thereby reducing the usefulness of readahead.
> Readahead.early uses a different file (/etc/readahead.early.files) to cache 
> useful system libraries, including a few kernel modules - for the 
> 2.6.3- kernel.
> Both readahead and readahead.early are installed as disabled. chkconfig 
> lists them as 'off' in all runlevels.
> Worse, cpuspeed.
> This is from an Athlon64 system, so it is possible that this behavior is 
> different on non powernow-k8 systems.
> On the CentOS4-x86_64 kernels, the cpuspeed-drivers are built into the 
> kernel. Here, cpu speed-management works, as the 
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver -file exists (tested for 
> in /etc/init.d/cpuspeed). On CentOS4-i386, the powernow-k8-module is not 
> built into the kernel, so the above test fails, and the cpuspeed startscript 
> exits.
> There seems to be a plan for this. The /etc/cpuspeed.conf file can specify a 
> DRIVER variable, but no attempt is made to insmod this, so even if this is 
> set, cpuspeed still fails. A simple fix is to check for the presence of the 
> above /sys entry, and if that is missing, modprobe $DRIVER. Without this, 
> cpuspeed will never work on my systems.
> Does it work elsewhere?

cpuspeed does work for powernow enabled AMD machines.

I don't disagree with any of your posts ... however, we will continue to
publish these RPMS exactly as they are released upstream.

I personally recommend that read ahead and read ahead early is turned
off ... and also cpuspeed unless you have a laptop and it works for you.
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