From: Preeti U Murthy <preeti@linux.vnet.ibm.com>
To: Frederic Weisbecker <fweisbec@gmail.com>,
LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 5/8] nohz: Restart the tick from irq exit
Date: Sun, 14 Jun 2015 14:48:38 +0530 [thread overview]
Message-ID: <557D46EE.2070701@linux.vnet.ibm.com> (raw)
In-Reply-To: <1434044168-23173-6-git-send-email-fweisbec@gmail.com>
On 06/11/2015 11:06 PM, Frederic Weisbecker wrote:
> Restart the tick when necessary from the irq exit path. It makes nohz
> full more flexible and allow it to piggyback the tick restart on the
> scheduler IPI in the future instead of sending a dedicated IPI that
> often doubles the scheduler IPI on task wakeup. This will require
You can piggy back on the scheduler ipi when you add a timer/hrtimer and
add a new task to the runqueue of the nohz_full cpus, since we call
resched_curr() in these code paths. But what about the calls to kick
nohz_full cpus by perf events and posix cpu timers ? These call sites
seem to be concerned about specifically waking up nohz_full cpus as far
as I can see. IOW there is no scheduling ipi that we can fall back on in
these paths.
> careful review of resched_curr() callers.
>
Regards
Preeti U Murthy
next prev parent reply other threads:[~2015-06-14 9:19 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 17:36 [PATCH 0/8] tick/nohz: Tick dependency quick check + cleanups Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 1/8] jiffies: Remove HZ > USEC_PER_SEC special case Frederic Weisbecker
2015-06-11 20:46 ` Rik van Riel
2015-06-11 17:36 ` [PATCH 2/8] apm32: Fix cputime == jiffies assumption Frederic Weisbecker
2015-06-11 20:47 ` Rik van Riel
2015-06-11 17:36 ` [PATCH 3/8] alpha: Fix jiffies based cputime assumption Frederic Weisbecker
2015-06-11 20:47 ` Rik van Riel
2015-06-11 17:36 ` [PATCH 4/8] nohz: Remove idle task special case Frederic Weisbecker
2015-06-11 20:47 ` Rik van Riel
2015-06-14 1:44 ` Preeti U Murthy
2015-07-07 14:45 ` Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 5/8] nohz: Restart the tick from irq exit Frederic Weisbecker
2015-06-11 20:48 ` Rik van Riel
2015-06-12 7:32 ` Peter Zijlstra
2015-06-12 12:38 ` Frederic Weisbecker
2015-06-12 12:59 ` Peter Zijlstra
2015-06-12 13:06 ` Frederic Weisbecker
2015-06-14 9:30 ` Preeti U Murthy
2015-07-07 14:23 ` Frederic Weisbecker
2015-06-14 9:18 ` Preeti U Murthy [this message]
2015-06-14 9:19 ` Preeti U Murthy
2015-07-07 14:20 ` Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 6/8] nohz: Move tick_nohz_restart_sched_tick() above its users Frederic Weisbecker
2015-06-11 20:48 ` Rik van Riel
2015-06-11 17:36 ` [PATCH 7/8] nohz: Evaluate tick dependency once on context switch Frederic Weisbecker
2015-06-11 20:46 ` Rik van Riel
2015-06-17 5:59 ` Preeti U Murthy
2015-07-07 14:30 ` Frederic Weisbecker
2015-06-12 7:36 ` Peter Zijlstra
2015-07-06 16:14 ` Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 8/8] nohz: Remove useless argument on tick_nohz_task_switch() Frederic Weisbecker
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