[mythtv-users] PREEMPT kernel with nvidia

Paul Bender pebender at san.rr.com
Thu Jan 3 17:24:51 UTC 2008

Paul Andreassen wrote:
> On Wednesday 02 January 2008 14:56, Chris Isip wrote:
>> On Jan 1, 2008 8:30 AM, Paul Andreassen <paulx at andreassen.com.au> wrote:
>>> Is it possible to have a PREEMPT kernel while using the closed source
>>> nVidia
>>> driver?
>>> I've compiled the stable Debian kernel 2.6.18 and the backported kernel
>>> 2.6.22, and both kill random programs. Its strange because it some times
>>> kills the game I'm running, sometime faults on boot up and once gcc
>>> actually
>>> died.
>> What benefit does a preempt kernel have over a regular kernel? I thought it
>> was important on a desktop system but not a server since user
>> responsiveness is not important on a server.   So I disabled it on the
>> kernel config.  I could be wrong.
> The idea of a preempt kernel is to reduce the time to respond to interrupts, 
> etc at the cost of amount of work done.  Good for games, mythfrontend, etc 
> where timing is important.
>> As far as the kernel killing things.  I encountered this with only one
>> program mysqld.  I think it was the kernel OOM killer. I notice that mysqld
>> keeps eating memory the longer it runs so now I restart it everyday.  Have
>> you checked the available memory with free when it starts killing things?
> The machine has got 3 Giga Bytes of RAM and the problem once occurred on boot 
> up.

On my dedicated Myth frontends, I have had the kernel configured with 
voluntary kernel preemption (PREEMPT_VOLUNTARY) and large block 
preemption (PREEMPT_BKL) for some time (at least since the 2.6.17 kernel 
(I am now on the 2.6.23 kernel)). The NVIDIA proprietary drivers work 
well and the frontend is responsive.

Some time ago, while using the 2.6.17 kernel, had tried configuring with 
kernel preemption (PREEMPT), this gave me problems with no benefit. As a 
result, I stopped using it.

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