System timer resolution is too low [solved]

[jagwah]

Apparently Linux kernels 2.6.13 and up have the System timer set at 250Hz, where as it used to be 1000Hz as I understand it. However if you try to run Rosegarden it will complain that the System timer resolution is to low, and it is apparently to low for midi. So basically the solution is to either get a Kernel that is pre compiled with a higher resolution, or compile it yourself and add the higher resolution. So now with Man2007 I'm going to have to do one or the other.

So, is there a Kernel available pre compiled with the higher timer resolution? (maybe one for multi media or something)

 

Can I just use one of the 2.6.12 series Kernels with Man2007?

 

I started trying to see if I could compile one myself with the Man2007 rc1, but I needed to install other stuff before I could even begin, and wasn't real sure where to get the packages from for 2007, so I thought I would just let it be until it was actually released and things were set up. Plus I don't really know what to expect when/if I did actually get to compiling the kernel for myself, is it all selfexplanatory, or would I be just lost?

 

One thing is for sure, I need a kernel with a higher timer resolution, so what is the best way to go?

Edited September 10, 2006 by jagwah

[scoonma]

Hi jagwah,

 

you wrote:

 

I started trying to see if I could compile one myself with the Man2007 rc1, but I needed to install other stuff before I could even begin, and wasn't real sure where to get the packages from for 2007, so I thought I would just let it be until it was actually released and things were set up. Plus I don't really know what to expect when/if I did actually get to compiling the kernel for myself, is it all selfexplanatory, or would I be just lost?

 

It *is* self-explanatory, but when you go through the procedure the first time, you'll have to read at least some manuals carefully and be willing to spend time and possibly some unsuccessfull attempts. However, it should be possible just to change the timer resolution, and leave any other option untouched. Thus you'd be more safe to get a working kernel; compared to trying a build, which perfectly suits your hardware and need. This may be alluring when you see the little world of options of its own, of which you likely do not to even know some or many names. This is the place of core access, and you can finetune your system to a level you decide on your own, near to it's physical maximum and personal liking. But the higher the level, the more reading and real learning is involved. Not everyone does like it or is able to take the time.

 

However, if you want to take basic steps on this road, take a free weekend (at least several hours) and consider the following reduced info:

 

 

1) Read the FAQs of this forum regarding kernel compilation

 

2) Install proper kernel sources (i.e. a stable version out of contrib repository patched to use with Mandriva, *not* the most actual from kernel.org ;-)

 

3) Do a root login on a terminal window and change directory to /usr/src/linux-2.x.y.z, with x.y.z reflecting the kernel version you're using (check with uname -a)

 

4) Read and try to understand the README file residing here as good as you can

 

5) Enter Documentation folder below, read and understand the Changes file here.

 

6) Install missing software being mentioned

 

7) Take the actual steps to build the kernel:

 

- Do "make menuconfig" for instance and change desired options (you find the option to set Timer Frequency at the bottom of the "Processor type and feature" menu).

 

- Do "make install" && "make modules_install" (this is for a 2.6.17 series kernel)

 

When everything went allright (you can ignore warnings, but not errors!), reboot and your new kernel.

 

One thing is for sure, I need a kernel with a higher timer resolution, so what is the best way to go?

 

:-) Which way is *best* you have to decide on your own. If you want to learn about your system from the inside, you can take the long road described above.

 

If you want to take a shortcut, you can use a 2.6.17.11-mm-desktop-2mdv kernel. Just checked it has the 1000Mhz option enabled by default. But this is the 32bit version (i.e. i586). Don't know about x86_64.

 

 

Cheers,

 

scoonma

[jagwah]

Thank you very much for taking the time to write that reply. Although the temtation to take the easy road and use the 2.6.17.11-mm-desktop-2mdv kernel you mentioned is strong and inviting, I think I will try and do a compile myself, at least I will see first hand what is involved, and I may just learn something, plus it doesn't really matter if I mess it up, I will be reinstalling everything once 2007 is released, plus I can always just use the pre compiled kerenel you mentioned if I fail to badly :)

 

So looks like I will be doing some reading and tinkering under the hood this weekend ...

 

Thanks again for the info.

[jagwah]

Success, my first Kernel compile and it worked out great, now Rosegarden fires up like it should, and I don't seem to have killed anything else. :D It was very tempting to start ripping stuff out that isn't needed while I was in there, but I resisted and just done what I had to, maybe next time. Good to see how it is done, now I won't be so worried if I have to do it again.

 

Thanks again for you help scoonma, it's greatly appreciated