Re: dyntick-idle CPU and node's qsmask

2018-11-21 Thread Paul E. McKenney
On Tue, Nov 20, 2018 at 08:37:22PM -0800, Joel Fernandes wrote: > On Tue, Nov 20, 2018 at 06:41:07PM -0800, Paul E. McKenney wrote: > [...] > > > > > I was thinking if we could simplify rcu_note_context_switch (the > > > > > parts that > > > > > call rcu_momentary_dyntick_idle), if we did the fol

Re: dyntick-idle CPU and node's qsmask

2018-11-20 Thread Joel Fernandes
On Tue, Nov 20, 2018 at 06:41:07PM -0800, Paul E. McKenney wrote: [...] > > > > I was thinking if we could simplify rcu_note_context_switch (the parts > > > > that > > > > call rcu_momentary_dyntick_idle), if we did the following in > > > > rcu_implicit_dynticks_qs. > > > > > > > > Since we alre

Re: dyntick-idle CPU and node's qsmask

2018-11-20 Thread Paul E. McKenney
On Tue, Nov 20, 2018 at 06:06:12PM -0800, Joel Fernandes wrote: > On Tue, Nov 20, 2018 at 02:28:14PM -0800, Paul E. McKenney wrote: > > On Tue, Nov 20, 2018 at 12:42:43PM -0800, Joel Fernandes wrote: > > > On Sun, Nov 11, 2018 at 10:36:18AM -0800, Paul E. McKenney wrote: > > > > On Sun, Nov 11, 201

Re: dyntick-idle CPU and node's qsmask

2018-11-20 Thread Joel Fernandes
On Tue, Nov 20, 2018 at 02:28:14PM -0800, Paul E. McKenney wrote: > On Tue, Nov 20, 2018 at 12:42:43PM -0800, Joel Fernandes wrote: > > On Sun, Nov 11, 2018 at 10:36:18AM -0800, Paul E. McKenney wrote: > > > On Sun, Nov 11, 2018 at 10:09:16AM -0800, Joel Fernandes wrote: > > > > On Sat, Nov 10, 201

Re: dyntick-idle CPU and node's qsmask

2018-11-20 Thread Paul E. McKenney
On Tue, Nov 20, 2018 at 02:28:13PM -0800, Paul E. McKenney wrote: > On Tue, Nov 20, 2018 at 12:42:43PM -0800, Joel Fernandes wrote: > > On Sun, Nov 11, 2018 at 10:36:18AM -0800, Paul E. McKenney wrote: > > > On Sun, Nov 11, 2018 at 10:09:16AM -0800, Joel Fernandes wrote: > > > > On Sat, Nov 10, 201

Re: dyntick-idle CPU and node's qsmask

2018-11-20 Thread Paul E. McKenney
On Tue, Nov 20, 2018 at 12:42:43PM -0800, Joel Fernandes wrote: > On Sun, Nov 11, 2018 at 10:36:18AM -0800, Paul E. McKenney wrote: > > On Sun, Nov 11, 2018 at 10:09:16AM -0800, Joel Fernandes wrote: > > > On Sat, Nov 10, 2018 at 08:22:10PM -0800, Paul E. McKenney wrote: > > > > On Sat, Nov 10, 201

Re: dyntick-idle CPU and node's qsmask

2018-11-20 Thread Joel Fernandes
On Sun, Nov 11, 2018 at 10:36:18AM -0800, Paul E. McKenney wrote: > On Sun, Nov 11, 2018 at 10:09:16AM -0800, Joel Fernandes wrote: > > On Sat, Nov 10, 2018 at 08:22:10PM -0800, Paul E. McKenney wrote: > > > On Sat, Nov 10, 2018 at 07:09:25PM -0800, Joel Fernandes wrote: > > > > On Sat, Nov 10, 201

Re: dyntick-idle CPU and node's qsmask

2018-11-11 Thread Joel Fernandes
On Sun, Nov 11, 2018 at 10:36:18AM -0800, Paul E. McKenney wrote: [..] > > > > > CPU will with high probability report its own quiescent state before > > > > > three > > > > > jiffies pass, in which case the cache misses on the rcu_data > > > > > structures > > > > > would be wasted motion. > > >

Re: dyntick-idle CPU and node's qsmask

2018-11-11 Thread Paul E. McKenney
On Sun, Nov 11, 2018 at 10:09:16AM -0800, Joel Fernandes wrote: > On Sat, Nov 10, 2018 at 08:22:10PM -0800, Paul E. McKenney wrote: > > On Sat, Nov 10, 2018 at 07:09:25PM -0800, Joel Fernandes wrote: > > > On Sat, Nov 10, 2018 at 03:04:36PM -0800, Paul E. McKenney wrote: > > > > On Sat, Nov 10, 201

Re: dyntick-idle CPU and node's qsmask

2018-11-11 Thread Joel Fernandes
On Sat, Nov 10, 2018 at 08:22:10PM -0800, Paul E. McKenney wrote: > On Sat, Nov 10, 2018 at 07:09:25PM -0800, Joel Fernandes wrote: > > On Sat, Nov 10, 2018 at 03:04:36PM -0800, Paul E. McKenney wrote: > > > On Sat, Nov 10, 2018 at 01:46:59PM -0800, Joel Fernandes wrote: > > > > Hi Paul and everyon

Re: dyntick-idle CPU and node's qsmask

2018-11-10 Thread Paul E. McKenney
On Sat, Nov 10, 2018 at 07:09:25PM -0800, Joel Fernandes wrote: > On Sat, Nov 10, 2018 at 03:04:36PM -0800, Paul E. McKenney wrote: > > On Sat, Nov 10, 2018 at 01:46:59PM -0800, Joel Fernandes wrote: > > > Hi Paul and everyone, > > > > > > I was tracing/studying the RCU code today in paul/dev bran

Re: dyntick-idle CPU and node's qsmask

2018-11-10 Thread Joel Fernandes
On Sat, Nov 10, 2018 at 03:04:36PM -0800, Paul E. McKenney wrote: > On Sat, Nov 10, 2018 at 01:46:59PM -0800, Joel Fernandes wrote: > > Hi Paul and everyone, > > > > I was tracing/studying the RCU code today in paul/dev branch and noticed > > that > > for dyntick-idle CPUs, the RCU GP thread is c

Re: dyntick-idle CPU and node's qsmask

2018-11-10 Thread Paul E. McKenney
On Sat, Nov 10, 2018 at 01:46:59PM -0800, Joel Fernandes wrote: > Hi Paul and everyone, > > I was tracing/studying the RCU code today in paul/dev branch and noticed that > for dyntick-idle CPUs, the RCU GP thread is clearing the rnp->qsmask > corresponding to the leaf node for the idle CPU, and re

dyntick-idle CPU and node's qsmask

2018-11-10 Thread Joel Fernandes
Hi Paul and everyone, I was tracing/studying the RCU code today in paul/dev branch and noticed that for dyntick-idle CPUs, the RCU GP thread is clearing the rnp->qsmask corresponding to the leaf node for the idle CPU, and reporting a QS on their behalf. rcu_sched-10[003]40.008039: rcu_fqs