Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

Bill Huey
2004-11-02T03:18:43Z

On Mon, Nov 01, 2004 at 11:51:25PM +0100, Florian Schmidt wrote:
[...lock debugging...]
> ack. understood. i was just asking since i don't have a second machine and
> thus am not really able to help with the deadlock debugging. so i figured i
> could at least do some timing. btw: even with deadlock detection, the
> results for 0.6.5 looked pretty good [in 10 minutes uptime ca.3-4% max
> jitter [30something usecs]. until the deadlock that is [i head three finds
> plus kernel compile at nice -10 running]..

The lock chains aren't that deep in Linux so the algorithmic complexity
is not going to hit some crazy polynomial time unless there's some seriously
nasty contention at a certain point in the kernel (billions of readers for
example against a write aquire). But when we start to see things like that
under pressure is when we need to start shortening the need for that/those
lock(s) for that/those critical section(s) in question.

bill