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Subject: Re: sched: Avoid SMT siblings in select_idle_sibling() if possible
From: Mike Galbraith <efault@gmx.de>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@elte.hu>, Paul Turner <pjt@google.com>
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Date: Thu, 17 Nov 2011 16:38:33 +0100
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On Thu, 2011-11-17 at 02:59 +0100, Mike Galbraith wrote:
> On Wed, 2011-11-16 at 10:37 -0800, Suresh Siddha wrote:

> > It should be ok. Isn't it?
> 
> Nope, wasn't ok.

Because you can't get to again: with a single E5620 package, it having
only SIBLING and MC domains.
 
again:
        for_each_domain(target, sd) {
                if (!smt && (sd->flags & SD_SHARE_CPUPOWER))
                        continue;

                if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) {
                        if (!smt) {
                                smt = 1;
                                goto again;