Message-ID: <1365589603.30071.37.camel@laptop>
Subject: Re: [RFC GIT PULL] nohz: Full dynticks rq clock handling
From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Alessio Igor Bogani <abogani@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Chris Metcalf <cmetcalf@tilera.com>, Christoph Lameter <cl@linux.com>,
        Geoff Levand <geoff@infradead.org>,
        Gilad Ben Yossef <gilad@benyossef.com>,
        Hakan Akkan <hakanakkan@gmail.com>,
        Li Zhong <zhong@linux.vnet.ibm.com>,
        Namhyung Kim <namhyung.kim@lge.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>, Paul Turner <pjt@google.com>,
        Mike Galbraith <efault@gmx.de>
Date: Wed, 10 Apr 2013 12:26:43 +0200
In-Reply-To: <1365266760-24725-1-git-send-email-fweisbec@gmail.com>
References: <1365266760-24725-1-git-send-email-fweisbec@gmail.com>
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Another thing I just noticed; our update_curr() assumes its called at
least once every 4 odd seconds (2^32 ns like).

update_curr() is 'required' for things like task runtime stats and
everything that hangs off of that like cputimers etc.

Now I'm not entirely sure how the nr_running==1 nohz case deals with
this, but I can imagine it might take a while. In this case we might
need to 'fix' update_curr() to not asume the time delta fits in 32
bits.

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