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

[Thomas Gleixner]

On Fri, 2004-10-29 at 10:02 +0200, Ingo Molnar wrote:
> there are multiple possibilities of how this ~700 usecs delay occured:
> 
>  - the kernel still has a wakeup bug. But this should be detected by the
>    tracer which measures the time between when the task hits the
>    runqueue and the task gets to execute on the CPU. Also, if there is a
>    critical section in the kernel that is 700 usecs long it would be
>    detected by _another_, independent timing/tracing mechanism that
>    measures critical sections. The likelyhood of both the scheduler
>    _and_ two independent kernel-tracers being buggy in the same way is
>    quite significantly low. (not to mention the user-space amlat tool
>    which seems to agree with the kernel instrumentation.)
> 

The sound subsystem uses a lot of sleep_on() variants. We know that they
are racy. Might this be related ?

tglx


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/