Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Paul E. McKenney
On Mon, Jun 23, 2014 at 08:57:35PM +0200, Peter Zijlstra wrote: > On Mon, Jun 23, 2014 at 10:33:08AM -0700, Paul E. McKenney wrote: > > On Mon, Jun 23, 2014 at 08:57:50AM -0700, Paul E. McKenney wrote: > > > On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: > > > > On Tue, Jun 17,

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Peter Zijlstra
On Mon, Jun 23, 2014 at 10:33:08AM -0700, Paul E. McKenney wrote: > On Mon, Jun 23, 2014 at 08:57:50AM -0700, Paul E. McKenney wrote: > > On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: > > > On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: > > > > Oh, and to

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Paul E. McKenney
On Mon, Jun 23, 2014 at 08:57:50AM -0700, Paul E. McKenney wrote: > On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: > > On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: > > > Oh, and to answer the implicit question... A properly configured 4096-CPU > > > system

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Paul E. McKenney
On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: > On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: > > Oh, and to answer the implicit question... A properly configured 4096-CPU > > system will have two funnel levels, with 64 nodes at the leaf level > > and a

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Peter Zijlstra
On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: > Oh, and to answer the implicit question... A properly configured 4096-CPU > system will have two funnel levels, with 64 nodes at the leaf level > and a single node at the root level. If the system is not properly > configured,

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Paul E. McKenney
On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: Oh, and to answer the implicit question... A properly configured 4096-CPU system will have two funnel levels, with 64 nodes at the leaf level and a single node

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Paul E. McKenney
On Mon, Jun 23, 2014 at 08:57:50AM -0700, Paul E. McKenney wrote: On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: Oh, and to answer the implicit question... A properly configured 4096-CPU system will have

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Peter Zijlstra
On Mon, Jun 23, 2014 at 10:33:08AM -0700, Paul E. McKenney wrote: On Mon, Jun 23, 2014 at 08:57:50AM -0700, Paul E. McKenney wrote: On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: Oh, and to answer the

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Paul E. McKenney
On Mon, Jun 23, 2014 at 08:57:35PM +0200, Peter Zijlstra wrote: On Mon, Jun 23, 2014 at 10:33:08AM -0700, Paul E. McKenney wrote: On Mon, Jun 23, 2014 at 08:57:50AM -0700, Paul E. McKenney wrote: On Mon, Jun 23, 2014 at 12:28:50PM +0200, Peter Zijlstra wrote: On Tue, Jun 17, 2014 at

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-23 Thread Peter Zijlstra
On Tue, Jun 17, 2014 at 10:37:17AM -0700, Paul E. McKenney wrote: Oh, and to answer the implicit question... A properly configured 4096-CPU system will have two funnel levels, with 64 nodes at the leaf level and a single node at the root level. If the system is not properly configured, it

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Waiman Long
On 06/17/2014 01:37 PM, Paul E. McKenney wrote: Oh, and to answer the implicit question... A properly configured 4096-CPU system will have two funnel levels, with 64 nodes at the leaf level and a single node at the root level. If the system is not properly configured, it will have three

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Pranith Kumar
On Tue, Jun 17, 2014 at 1:10 PM, Paul E. McKenney wrote: > > Pranith, Romanov: You do -not-, repeat -not-, get to shoot from the hip > with this code. You absolutely need to understand what it is doing and > why before you try hacking on it. Otherwise, all that will happen is > that you will

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Tue, Jun 17, 2014 at 10:11:16AM -0700, Paul E. McKenney wrote: > On Tue, Jun 17, 2014 at 12:56:22PM -0400, Waiman Long wrote: > > On 06/17/2014 12:01 PM, Romanov Arya wrote: > > >On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney > > > wrote: > > >>On Mon, Jun 16, 2014 at 10:55:29PM -0400,

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Tue, Jun 17, 2014 at 12:56:22PM -0400, Waiman Long wrote: > On 06/17/2014 12:01 PM, Romanov Arya wrote: > >On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney > > wrote: > >>On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: > >>>This might sound really naive, but please bear with

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Tue, Jun 17, 2014 at 12:01:28PM -0400, Romanov Arya wrote: > On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney > wrote: > > On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: > >> This might sound really naive, but please bear with me. > >> > >> force_quiescent_state() used to do

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Waiman Long
On 06/17/2014 12:01 PM, Romanov Arya wrote: On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney wrote: On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: This might sound really naive, but please bear with me. force_quiescent_state() used to do a lot of things in the past in

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Romanov Arya
On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney wrote: > On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: >> This might sound really naive, but please bear with me. >> >> force_quiescent_state() used to do a lot of things in the past in addition to >> forcing a quiescent state.

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: > This might sound really naive, but please bear with me. > > force_quiescent_state() used to do a lot of things in the past in addition to > forcing a quiescent state. (In my reading of the mailing list I found state > transitions

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: This might sound really naive, but please bear with me. force_quiescent_state() used to do a lot of things in the past in addition to forcing a quiescent state. (In my reading of the mailing list I found state transitions for

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Romanov Arya
On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: This might sound really naive, but please bear with me. force_quiescent_state() used to do a lot of things in the past in addition to forcing a

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Waiman Long
On 06/17/2014 12:01 PM, Romanov Arya wrote: On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: This might sound really naive, but please bear with me. force_quiescent_state() used to do a lot of

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Tue, Jun 17, 2014 at 12:01:28PM -0400, Romanov Arya wrote: On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: This might sound really naive, but please bear with me.

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Tue, Jun 17, 2014 at 12:56:22PM -0400, Waiman Long wrote: On 06/17/2014 12:01 PM, Romanov Arya wrote: On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Mon, Jun 16, 2014 at 10:55:29PM -0400, Pranith Kumar wrote: This might sound really naive, but

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Paul E. McKenney
On Tue, Jun 17, 2014 at 10:11:16AM -0700, Paul E. McKenney wrote: On Tue, Jun 17, 2014 at 12:56:22PM -0400, Waiman Long wrote: On 06/17/2014 12:01 PM, Romanov Arya wrote: On Tue, Jun 17, 2014 at 10:54 AM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: On Mon, Jun 16, 2014 at

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Pranith Kumar
On Tue, Jun 17, 2014 at 1:10 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: Pranith, Romanov: You do -not-, repeat -not-, get to shoot from the hip with this code. You absolutely need to understand what it is doing and why before you try hacking on it. Otherwise, all that will

Re: [RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-17 Thread Waiman Long
On 06/17/2014 01:37 PM, Paul E. McKenney wrote: Oh, and to answer the implicit question... A properly configured 4096-CPU system will have two funnel levels, with 64 nodes at the leaf level and a single node at the root level. If the system is not properly configured, it will have three

[RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-16 Thread Pranith Kumar
This might sound really naive, but please bear with me. force_quiescent_state() used to do a lot of things in the past in addition to forcing a quiescent state. (In my reading of the mailing list I found state transitions for one). Now according to the code, what is being done is multiple

[RFC PATCH 1/1] kernel/rcu/tree.c: simplify force_quiescent_state()

2014-06-16 Thread Pranith Kumar
This might sound really naive, but please bear with me. force_quiescent_state() used to do a lot of things in the past in addition to forcing a quiescent state. (In my reading of the mailing list I found state transitions for one). Now according to the code, what is being done is multiple