From: josh@joshtriplett.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,
niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
sbw@mit.edu
Subject: Re: [PATCH tip/core/rcu 0/5] Fix for cond_resched performance regression
Date: Fri, 20 Jun 2014 12:04:34 -0700 [thread overview]
Message-ID: <20140620190434.GA22178@cloud> (raw)
In-Reply-To: <20140620183249.GA6325@linux.vnet.ibm.com>
On Fri, Jun 20, 2014 at 11:32:49AM -0700, Paul E. McKenney wrote:
> Hello!
>
> This series contains changes to address the performance regressions
> introduced by commit ac1bea85781e (Make cond_resched() report RCU
> quiescent states), which was in turn fixing a problem where tasks looping
> in the kernel could delay RCU grace periods. The changes in this series
> are as follows:
>
> 1. Reduce the overhead of checking added to cond_resched() and friends.
>
> 2. Add a new cond_resched_rcu_qs() to provide RCU quiescent states
> even if cond_resched() should stop doing so.
>
> 3. Add a new RCU_COND_RESCHED_QS to prevent cond_resched() from
> reporting RCU quiescent states.
>
> 4. Prevent rcutorture testing from reporting spurious RCU CPU stall
> warnings, and also to test RCU_COND_RESCHED_QS.
>
> 5. Provides a boot/sysfs rcutree.jiffies_till_cond_resched_qs
> parameter to replace the magic "7".
For all five patches:
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Glad to see this doesn't add any overhead to rcutiny.
- Josh Triplett
next prev parent reply other threads:[~2014-06-20 19:04 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-20 18:32 [PATCH tip/core/rcu 0/5] Fix for cond_resched performance regression Paul E. McKenney
2014-06-20 18:33 ` [PATCH RFC tip/core/rcu 1/5] rcu: Reduce overhead of cond_resched() checks for RCU Paul E. McKenney
2014-06-20 18:33 ` [PATCH RFC tip/core/rcu 2/5] rcu: Provide cond_resched_rcu_qs() to force quiescent states in long loops Paul E. McKenney
2014-06-20 18:33 ` [PATCH RFC tip/core/rcu 3/5] rcu: Add RCU_COND_RESCHED_QS for large systems Paul E. McKenney
2014-06-20 18:33 ` [PATCH RFC tip/core/rcu 4/5] rcutorture: Suppress spurious RCU CPU stall warnings Paul E. McKenney
2014-06-20 18:33 ` [PATCH RFC tip/core/rcu 5/5] rcu: Add boot/sysfs control for RCU cond_resched() help solicitation Paul E. McKenney
2014-06-23 16:43 ` [PATCH RFC tip/core/rcu 1/5] rcu: Reduce overhead of cond_resched() checks for RCU Oleg Nesterov
2014-06-23 17:36 ` Paul E. McKenney
2014-06-23 18:35 ` Oleg Nesterov
2014-06-24 0:18 ` Paul E. McKenney
2014-07-22 4:35 ` Pranith Kumar
2014-07-22 4:52 ` Pranith Kumar
2014-07-22 11:07 ` Paul E. McKenney
2014-07-22 11:06 ` Paul E. McKenney
2014-06-20 19:04 ` josh [this message]
2014-06-20 22:04 ` [PATCH tip/core/rcu 0/5] Fix for cond_resched performance regression Paul E. McKenney
2014-06-20 19:12 ` Paul E. McKenney
2014-06-20 21:24 ` josh
2014-06-20 22:11 ` Paul E. McKenney
2014-06-20 22:39 ` josh
2014-06-20 23:30 ` Paul E. McKenney
2014-06-20 23:52 ` josh
2014-06-21 0:14 ` Paul E. McKenney
2014-06-21 0:36 ` Paul E. McKenney
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