From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org,
dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com,
fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com
Subject: Re: [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods
Date: Fri, 20 Feb 2015 17:54:09 +0100 [thread overview]
Message-ID: <20150220165409.GU5029@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150220163737.GL5745@linux.vnet.ibm.com>
On Fri, Feb 20, 2015 at 08:37:37AM -0800, Paul E. McKenney wrote:
> On Fri, Feb 20, 2015 at 10:11:07AM +0100, Peter Zijlstra wrote:
> > So I though we wanted to get rid / limit the expedited stuff because its
> > IPI happy, and here its spreading.
>
> Well, at least it no longer IPIs idle CPUs. ;-)
>
> And this is during boot, when a few extra IPIs should not be a big deal.
Well the one application now is during boot; but you expose the
interface for all to use, and therefore someone will.
> > Does it really make a machine boot much faster? Why are people using
> > synchronous gp primitives if they care about speed? Should we not fix
> > that instead?
>
> The report I heard was that it provided 10-15% faster boot times.
That's not insignificant; got more details? I think we should really
look at why people are using the sync primitives.
next prev parent reply other threads:[~2015-02-20 16:54 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-20 5:08 [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods Paul E. McKenney
2015-02-20 5:09 ` [PATCH v2 RFC tip/core/rcu 1/4] rcu: Provide rcu_expedite_gp() and rcu_unexpedite_gp() Paul E. McKenney
2015-02-20 5:09 ` [PATCH v2 RFC tip/core/rcu 2/4] rcu: Add rcu_expedite_gp() and rcu_unexpedite_gp() to rcutorture Paul E. McKenney
2015-02-20 5:09 ` [PATCH v2 RFC tip/core/rcu 3/4] rcu: Update from rcu_expedited variable to rcu_gp_is_expedited() Paul E. McKenney
2015-02-20 5:09 ` [PATCH v2 RFC tip/core/rcu 4/4] rcu: Add Kconfig option to expedite grace periods during boot Paul E. McKenney
2015-02-20 9:11 ` [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods Peter Zijlstra
2015-02-20 16:37 ` Paul E. McKenney
2015-02-20 16:54 ` Peter Zijlstra [this message]
2015-02-20 17:14 ` Paul E. McKenney
2015-02-20 17:32 ` Arjan van de Ven
2015-02-20 17:43 ` Peter Zijlstra
2015-02-20 17:45 ` Arjan van de Ven
2015-02-21 16:08 ` Peter Zijlstra
2015-02-22 1:43 ` Paul E. McKenney
2015-02-20 18:38 ` Paul E. McKenney
2015-02-21 16:11 ` Peter Zijlstra
2015-02-21 17:59 ` Paul E. McKenney
2015-02-20 18:27 ` Paul E. McKenney
2015-02-20 18:29 ` Arjan van de Ven
2015-02-20 18:39 ` Paul E. McKenney
2015-02-21 15:51 ` Arjan van de Ven
2015-02-21 18:00 ` Paul E. McKenney
2015-02-22 3:58 ` Josh Triplett
2015-02-22 6:10 ` Paul E. McKenney
2015-02-22 18:31 ` Arjan van de Ven
2015-02-22 18:48 ` Josh Triplett
2015-02-21 6:04 ` Josh Triplett
2015-02-21 15:12 ` Mathieu Desnoyers
2015-02-21 23:58 ` Paul E. McKenney
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