From: Arjan van de Ven <arjan@linux.intel.com>
To: paulmck@linux.vnet.ibm.com, Peter Zijlstra <peterz@infradead.org>
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 09:32:39 -0800 [thread overview]
Message-ID: <54E76FB7.4060005@linux.intel.com> (raw)
In-Reply-To: <20150220171442.GM5745@linux.vnet.ibm.com>
>>>> 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.
>
> I must defer to the people who took the exact measurements.
>
> But yes, once I have that info, I should add it to the commit log.
so the two most obvious cases are
Registering sysrq keys ... even when the old key code had no handler
(have a patch pending for this)
registering idle handlers
(this is more tricky, it's very obvious abuse but the fix is less clear)
there's a few others as well that I'm chasing down...
.. but the flip side, prior to running ring 3 code, why NOT do fast expedites?
next prev parent reply other threads:[~2015-02-20 17:32 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
2015-02-20 17:14 ` Paul E. McKenney
2015-02-20 17:32 ` Arjan van de Ven [this message]
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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