From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Threaded irqs + 100% CPU RT task = RCU stall
Date: Wed, 6 Mar 2013 09:16:48 -0800 [thread overview]
Message-ID: <20130306171648.GO3268@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1303061651360.22263@ionos>
On Wed, Mar 06, 2013 at 04:58:54PM +0100, Thomas Gleixner wrote:
> On Wed, 6 Mar 2013, Paul Gortmaker wrote:
> > So, I guess the question is, whether we want to try and make the system
> > fail in a more meaningful way -- kind of like the rt throttling message
> > does - as it lets users know they've hit the wall? Something watching
>
> That Joe Doe should have noticed the throttler message, which came
> before the stall, shouldn't he?
>
> > for kstat_incr_softirqs traffic perhaps? Or other options?
>
> The rcu stall detector could use the softirq counter and if it did not
> change in the stall period print: "Caused by softirq starvation" or
> something like that.
The idea is to (at grace-period start) take a snapshot of the CPU's
value of kstat.softirqs[RCU_SOFTIRQ], then check it at stall time, right?
Or do I have the wrong softirq counter?
Thanx, Paul
next prev parent reply other threads:[~2013-03-06 17:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 15:49 Threaded irqs + 100% CPU RT task = RCU stall Paul Gortmaker
2013-03-06 15:58 ` Thomas Gleixner
2013-03-06 16:14 ` Paul Gortmaker
2013-03-06 17:16 ` Paul E. McKenney [this message]
2013-03-06 19:11 ` Thomas Gleixner
2013-03-06 21:45 ` Paul E. McKenney
2013-03-11 17:54 ` Sebastian Andrzej Siewior
2013-03-13 21:03 ` Paul Gortmaker
2013-03-13 21:28 ` Paul E. McKenney
2013-03-13 21:35 ` Paul E. McKenney
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