From: Peter Zijlstra <peterz@infradead.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>,
paulmck@linux.vnet.ibm.com, linux-rt-users@vger.kernel.org,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
Clark Williams <williams@redhat.com>
Subject: Re: [PATCH 2/2] timer: really raise softirq if there is irq_work to do
Date: Fri, 31 Jan 2014 21:05:35 +0100 [thread overview]
Message-ID: <20140131200535.GR5002@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <52EBFE1D.4020201@linutronix.de>
On Fri, Jan 31, 2014 at 08:48:45PM +0100, Sebastian Andrzej Siewior wrote:
>
> How "bad" is it? Is this something generic or just not getting
> perf events fast enough out? Most users don't seem to require small
> latencies.
I have vague memories of there being an actual perf problem if there's a
hole between the NMI/IRQ triggering the irq_work and the interrupt
running the work.
I should have some notes on it somewhere and an todo entry to plug the
hole.
But note that the MCE code also uses irq_work, they really _need_ to be
fast because the system might be crumbling under their feet.
next prev parent reply other threads:[~2014-01-31 20:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-31 14:34 [PATCH 1/2] irq_work: allow certain work in hard irq context Sebastian Andrzej Siewior
2014-01-31 14:34 ` [PATCH 2/2] timer: really raise softirq if there is irq_work to do Sebastian Andrzej Siewior
2014-01-31 17:07 ` Steven Rostedt
2014-01-31 17:11 ` Steven Rostedt
2014-01-31 17:42 ` Paul E. McKenney
2014-01-31 17:57 ` Steven Rostedt
2014-01-31 19:03 ` Paul E. McKenney
2014-01-31 19:26 ` Sebastian Andrzej Siewior
2014-01-31 19:34 ` Steven Rostedt
2014-01-31 19:48 ` Sebastian Andrzej Siewior
2014-01-31 19:56 ` Steven Rostedt
2014-01-31 20:05 ` Peter Zijlstra [this message]
2014-01-31 20:23 ` Sebastian Andrzej Siewior
2014-01-31 20:29 ` Peter Zijlstra
2014-01-31 19:54 ` Peter Zijlstra
2014-01-31 19:06 ` Sebastian Andrzej Siewior
2014-02-02 4:22 ` [PATCH 1/2] irq_work: allow certain work in hard irq context Mike Galbraith
2014-02-02 20:10 ` Sebastian Andrzej Siewior
2014-02-03 2:43 ` Mike Galbraith
2014-02-03 4:00 ` Mike Galbraith
2014-02-03 8:31 ` Sebastian Andrzej Siewior
2014-02-03 9:26 ` Mike Galbraith
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