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Date:   Wed, 14 Sep 2011 17:12:27 +0200
From:   Ralf Baechle <ralf@linux-mips.org>
To:     "Kevin D. Kissell" <kevink@paralogos.com>
Cc:     "Edgar E. Iglesias" <edgar.iglesias@gmail.com>,
        David Daney <david.daney@cavium.com>, linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: SMTC: Correct saving of CP0_STATUS
Message-ID: <20110914151227.GA13290@linux-mips.org>
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On Tue, Aug 30, 2011 at 09:54:53AM -0700, Kevin D. Kissell wrote:

> It could very well have been a QEMU issue.  At the time, I did spend
> a while staring at the diffs between the working and non-working
> kernel sources and I was unable to spot anything obviously suspect.
> > It makes me wonder, what is the state of SMTC kernels? Are they widely
> > used and considered stable?
> > Or is the SMP mode (1 TC per VPE) the common choice?
> The virtual SMP mode is far more common.  SMTC has the advantage
> that it allows the maximum throughput to be extracted from a 34K
> core - depending on the application/benchmark, the "sweet spot"
> may be more than 2 concurrent threads - but it's less well maintained.

Not to mention that SMTC was developed for a single 34K core.  It has
never been pimped up to support multi-core systems such as the 1004K
which would add some considerable complexity.

  Ralf