Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-10 Thread Paul E. McKenney
On Tue, Dec 10, 2013 at 03:37:03PM +0100, Frederic Weisbecker wrote: > On Wed, Dec 04, 2013 at 06:50:37PM -0800, Paul E. McKenney wrote: > > On Thu, Dec 05, 2013 at 02:20:55AM +0100, Frederic Weisbecker wrote: > > > On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: > > > > Hello,

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-10 Thread Frederic Weisbecker
On Wed, Dec 04, 2013 at 06:50:37PM -0800, Paul E. McKenney wrote: > On Thu, Dec 05, 2013 at 02:20:55AM +0100, Frederic Weisbecker wrote: > > On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: > > > Hello, Frederic, > > > > > > Just realized that I could further decrease RT latency

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-10 Thread Frederic Weisbecker
On Wed, Dec 04, 2013 at 06:50:37PM -0800, Paul E. McKenney wrote: On Thu, Dec 05, 2013 at 02:20:55AM +0100, Frederic Weisbecker wrote: On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: Hello, Frederic, Just realized that I could further decrease RT latency of one of my

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-10 Thread Paul E. McKenney
On Tue, Dec 10, 2013 at 03:37:03PM +0100, Frederic Weisbecker wrote: On Wed, Dec 04, 2013 at 06:50:37PM -0800, Paul E. McKenney wrote: On Thu, Dec 05, 2013 at 02:20:55AM +0100, Frederic Weisbecker wrote: On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: Hello, Frederic,

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-04 Thread Paul E. McKenney
On Thu, Dec 05, 2013 at 02:20:55AM +0100, Frederic Weisbecker wrote: > On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: > > Hello, Frederic, > > > > Just realized that I could further decrease RT latency of one of my "shut > > up RCU on NO_HZ_FULL CPUs" patches if I relied on CPU

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-04 Thread Frederic Weisbecker
On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: > Hello, Frederic, > > Just realized that I could further decrease RT latency of one of my "shut > up RCU on NO_HZ_FULL CPUs" patches if I relied on CPU 0 always having > a scheduling-clock tick unless the entire system is idle.

Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-04 Thread Paul E. McKenney
Hello, Frederic, Just realized that I could further decrease RT latency of one of my "shut up RCU on NO_HZ_FULL CPUs" patches if I relied on CPU 0 always having a scheduling-clock tick unless the entire system is idle. The trick is that I could then rely on CPU 0 to detect RCU CPU stall

Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-04 Thread Paul E. McKenney
Hello, Frederic, Just realized that I could further decrease RT latency of one of my shut up RCU on NO_HZ_FULL CPUs patches if I relied on CPU 0 always having a scheduling-clock tick unless the entire system is idle. The trick is that I could then rely on CPU 0 to detect RCU CPU stall warnings,

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-04 Thread Frederic Weisbecker
On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: Hello, Frederic, Just realized that I could further decrease RT latency of one of my shut up RCU on NO_HZ_FULL CPUs patches if I relied on CPU 0 always having a scheduling-clock tick unless the entire system is idle. The

Re: Will CPU 0 be forever prohibited from NO_HZ_FULL status?

2013-12-04 Thread Paul E. McKenney
On Thu, Dec 05, 2013 at 02:20:55AM +0100, Frederic Weisbecker wrote: On Wed, Dec 04, 2013 at 11:39:57AM -0800, Paul E. McKenney wrote: Hello, Frederic, Just realized that I could further decrease RT latency of one of my shut up RCU on NO_HZ_FULL CPUs patches if I relied on CPU 0 always