Re: PI BUG with -rt13

[Dinakar Guniguntala <dino@in.ibm.com>]

On Thu, Nov 24, 2005 at 08:56:06PM -0800, david singleton wrote:
> On Nov 24, 2005, at 12:32 PM, Dinakar Guniguntala wrote:
> 
> >>I just noticed with the above fix, Paul's testcase completely
> >>hangs up and when killed I hit the BUG mentioned below.
> >>Till -rt13, this testcase just ran to completion
> >
> >Forgot to mention that I notice the same failure with -rt15 as well
> 
> Good news and bad news.
> Good news.  This test doesn't exercise the robust futex code.
> Pthread mutexes that want priority queuing, priority inheritance and/or 
> robustness must have either  the robust (PTHREAD_MUTEX_ROBUST_NP) 
> attribute set and/or the PTHREAD_PRIO_INHERIT attribute set at mutex
> creation time.

Davi, Thank you for looking into this

Yes, this particular testcase does not exercise the robust futex code.
However, the testcase only hangs when I apply your fix on top of
 -rt13. A Vanilla -rt13 works fine

> Now a question before the bad news,    Are you in the OOM path when you
> think the system is hung?  What does 'top' say about freemem and 
> available and used swap space?

Since one of the threads is a SCHED_FIFO, the system takes forever
to respond to simple commands like ls/ps. I'll get back on this

> 
> If you are not in the OOM path then the bad news is this looks like an 
> SMP timer problem.
> 

	-Dinakar