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From: Steven Rostedt <rostedt@goodmis.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Kalesh Singh <kaleshsingh@google.com>,
	Suren Baghdasaryan <surenb@google.com>,
	kernel-team <kernel-team@android.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Tejun Heo <tj@kernel.org>, Tim Murray <timmurray@google.com>,
	Wei Wang <wvw@google.com>, Kyle Lin <kylelin@google.com>,
	Chunwei Lu <chunweilu@google.com>, Lulu Wang <luluw@google.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Neeraj Upadhyay <quic_neeraju@quicinc.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>, rcu <rcu@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] EXP rcu: Move expedited grace period (GP) work to RT kthread_worker
Date: Fri, 8 Apr 2022 11:39:46 -0400	[thread overview]
Message-ID: <20220408113946.056c083e@gandalf.local.home> (raw)
In-Reply-To: <CAEXW_YSqY2nFZrn4AjpUzJ+dwZc7jaVMG9RG5gvTyb3zFYWtQA@mail.gmail.com>

On Fri, 8 Apr 2022 06:21:03 -0400
Joel Fernandes <joel@joelfernandes.org> wrote:

> > +       default !PREEMPT_RT && NR_CPUS <= 32  
> 
> What is the benefit of turning it off on PREEMPT_RT, even if
> PREEMPT_RT does not use expedited GPs much post-boot? I would think in
> the future if PREEMPT_RT ever uses expedited GPs, they would want this
> feature even more. I'd rather be future-proof now as I don't see any
> advantages of disabling it on !PREEMPT_RT (And a drawback that the fix
> won't apply to those systems). Also will keep the config simple.

The default kthread priority is 1. This should not affect PREEMPT_RT, as
PREEMPT_RT users are usually more concerned by the performance of their
higher priority tasks. Priority 1 is not considered an issue.

I do not see why PREEMPT_RT is special here. Why was it singled out?

-- Steve

  parent reply	other threads:[~2022-04-08 15:39 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-08  4:57 [PATCH v2] EXP rcu: Move expedited grace period (GP) work to RT kthread_worker Kalesh Singh
2022-04-08 10:21 ` Joel Fernandes
2022-04-08 15:25   ` Paul E. McKenney
2022-04-08 15:39   ` Steven Rostedt [this message]
2022-04-08 15:58     ` Paul E. McKenney
2022-04-08 21:27       ` Steven Rostedt
2022-04-08 10:42 ` Joel Fernandes
2022-04-08 14:34   ` Paul E. McKenney
2022-04-08 14:41     ` Joel Fernandes
2022-04-08 15:34       ` Paul E. McKenney
2022-04-08 17:14         ` Joel Fernandes
2022-04-08 17:39           ` Paul E. McKenney
2022-04-08 17:53             ` Kalesh Singh
2022-04-08 21:42               ` Steven Rostedt
2022-04-08 22:06                 ` Kalesh Singh
     [not found]             ` <20220409071740.6024-1-hdanton@sina.com>
2022-04-09 15:56               ` Paul E. McKenney
     [not found]               ` <20220413113711.1263-1-hdanton@sina.com>
2022-04-13 14:07                 ` Paul E. McKenney
2022-04-13 17:21                   ` Joel Fernandes
2022-04-13 18:07                     ` Paul E. McKenney

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