Date: Mon, 7 Nov 2016 18:30:30 +0100
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        "Michael S. Tsirkin" <mst@redhat.com>, Julia Cartwright <julia@ni.com>,
        Luiz Capitulino <lcapitulino@redhat.com>,
        linux-rt-users@vger.kernel.org, Josh Triplett <josh@joshtriplett.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rcu: update: make RCU_EXPEDITE_BOOT default
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On 2016-11-07 12:19:39 [-0500], Steven Rostedt wrote:
> I agree, but if this creates a boot time regression in large machines,
> it may not be warranted.
> 
> I know Linus usually doesn't like options with default y, but this may
> be one of those exceptions. Perhaps we should make it on by default and
> say in the config "if you have a machine with 100s or 1000s of CPUs,
> you may want to disable this".

The default could change if we know where the limit is. I have access to
a box with approx 140 CPUs so I could check there if it is already bad.
But everything above that / in the 1000 range is a different story.

> -- Steve

Sebastian