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Message-ID: <1331208028.11248.384.camel@twins>
Subject: Re: runnable tasks never making it to a runqueue where they can run?
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Roland Dreier <roland@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Paul Turner <pjt@google.com>, Venkatesh Pallipadi <venki@google.com>,
        Suresh Siddha <suresh.b.siddha@intel.com>
Date: Thu, 08 Mar 2012 13:00:28 +0100
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On Thu, 2012-03-08 at 17:25 +0530, Srivatsa Vaddagiri wrote:
> * Peter Zijlstra <a.p.zijlstra@chello.nl> [2012-03-08 11:28:00]:
> 
> > select_task_rq_fair() will very likely end up in select_idle_sibling()
> > which will never select the smt1 if smt0 is idle
> 
> s/idle/busy?

Uhm, yeah ;-)

> > (even if smt0 isn't in
> > the cpus allowed mask) -- Vatsa is currently reworking that area, this
> > is something he might want to consider.
> 
> The patch I sent couple of days back should likely fix this issue:
> 
> http://marc.info/?l=linux-kernel&m=133096114129607&w=2

Ah, thanks for reminding me, I need to go stare at that!