From: Frederic Weisbecker <fweisbec@gmail.com>
To: Christoph Lameter <cl@linux.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org,
Gilad Ben-Yossef <gilad@benyossef.com>, Tejun Heo <tj@kernel.org>,
John Stultz <john.stultz@linaro.org>,
Mike Frysinger <vapier@gentoo.org>,
Minchan Kim <minchan.kim@gmail.com>,
Hakan Akkan <hakanakkan@gmail.com>,
Max Krasnyansky <maxk@qti.qualcomm.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Hugh Dickins <hughd@google.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [NOHZ] Remove scheduler_tick_max_deferment
Date: Tue, 11 Nov 2014 16:36:55 +0100 [thread overview]
Message-ID: <20141111153653.GB3216@lerouge> (raw)
In-Reply-To: <alpine.DEB.2.11.1411110857480.5148@gentwo.org>
On Tue, Nov 11, 2014 at 08:58:35AM -0600, Christoph Lameter wrote:
> On Mon, 10 Nov 2014, Frederic Weisbecker wrote:
>
> > Ok, I confess we moved part of that housekeeping to the syscall/exception/interrupt
> > entry path. We did that for cputime accounting and RCU. And it's possible to
> > even do that for timekeeping. But then the kernel entrypoint is going to be extremely
> > costly. It's worth CPU 0 as a sacrificial lamb.
>
> Well we can redirect to the scheduler setting the task flag and handle
> costly stuff there if necessary?
"there" here is the syscall/exception/interrupt entry path. And like I said, updating
timekeeping from these places is overkill (although we do it in interrupt entry on
dynticks-idle, but we don't have timekeeping when all system is idle).
next prev parent reply other threads:[~2014-11-11 15:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-31 16:01 [NOHZ] Remove scheduler_tick_max_deferment Christoph Lameter
2014-11-01 19:18 ` Thomas Gleixner
2014-11-01 21:52 ` Christoph Lameter
2014-11-01 22:33 ` Thomas Gleixner
2014-11-06 17:24 ` Christoph Lameter
2014-11-10 7:11 ` Viresh Kumar
2014-11-10 15:31 ` Paul E. McKenney
2014-11-10 16:21 ` Christoph Lameter
2014-11-10 18:26 ` Christoph Lameter
2014-11-11 17:15 ` Future of NOHZ full/isolation development (was Re: [NOHZ] Remove scheduler_tick_max_deferment) Frederic Weisbecker
2014-11-11 17:39 ` Paul E. McKenney
2014-11-11 18:00 ` Christoph Lameter
2014-11-12 6:11 ` Viresh Kumar
2014-11-12 13:54 ` Frederic Weisbecker
2014-11-12 14:56 ` Viresh Kumar
2014-11-12 15:06 ` Peter Zijlstra
2014-11-12 15:16 ` Viresh Kumar
2014-11-13 7:22 ` Viresh Kumar
2014-11-10 16:19 ` [NOHZ] Remove scheduler_tick_max_deferment Christoph Lameter
2014-11-10 22:43 ` Frederic Weisbecker
2014-11-11 14:58 ` Christoph Lameter
2014-11-11 15:36 ` Frederic Weisbecker [this message]
2014-11-11 17:08 ` Christoph Lameter
2014-11-10 20:26 ` Frederic Weisbecker
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