Re: [PATCH 1/7] rcu/segcblist: Prevent useless GP start if no CBs to accelerate

2020-06-18 Thread Joel Fernandes
On Thu, Jun 18, 2020 at 04:09:34PM -0700, Paul E. McKenney wrote: > On Thu, Jun 18, 2020 at 03:11:19PM -0700, Paul E. McKenney wrote: > > On Thu, Jun 18, 2020 at 04:29:49PM -0400, Joel Fernandes (Google) wrote: > > > > First, this looks like a very nice optimization, thank you! Thanks! > > >

Re: [PATCH 1/7] rcu/segcblist: Prevent useless GP start if no CBs to accelerate

2020-06-18 Thread Paul E. McKenney
On Thu, Jun 18, 2020 at 03:11:19PM -0700, Paul E. McKenney wrote: > On Thu, Jun 18, 2020 at 04:29:49PM -0400, Joel Fernandes (Google) wrote: > > First, this looks like a very nice optimization, thank you! > > > rcu_segcblist_accelerate() returns true if a GP is to be > > started/requested and

Re: [PATCH 1/7] rcu/segcblist: Prevent useless GP start if no CBs to accelerate

2020-06-18 Thread Paul E. McKenney
On Thu, Jun 18, 2020 at 04:29:49PM -0400, Joel Fernandes (Google) wrote: First, this looks like a very nice optimization, thank you! > rcu_segcblist_accelerate() returns true if a GP is to be > started/requested and false if not. During tracing, I found that it is > asking that GPs be requested

[PATCH 1/7] rcu/segcblist: Prevent useless GP start if no CBs to accelerate

2020-06-18 Thread Joel Fernandes (Google)
rcu_segcblist_accelerate() returns true if a GP is to be started/requested and false if not. During tracing, I found that it is asking that GPs be requested The exact flow seems to be something like: 1. Callbacks are queued on CPU A - into the NEXT list. 2. softirq runs on CPU A, accelerate all