Re: [v7 0/8] Reduce cross CPU IPI interference

From: Gilad Ben-Yossef
Date: Fri Feb 10 2012 - 15:33:15 EST


[Sent originally to Peter only by some weird gmail quirk. Re sending to all]

On Fri, Feb 10, 2012 at 8:33 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> On Thu, 2012-02-02 at 10:41 -0500, Chris Metcalf wrote:
>> At Tilera we have been supporting a "dataplane" mode (aka Zero Overhead
>> Linux - the marketing name).  This is configured on a per-cpu basis, and in
>> addition to setting isolcpus for those nodes, also suppresses various
>> things that might otherwise run (soft lockup detection, vmstat work,
>> etc.).
>
> See that's wrong.. it starts being wrong by depending on cpuisol and
> goes from there.

Actually, correct me if I'm wrong Chris, but I don't think the idea is
to adopt Tilera dataplane mode to mainline but rather treat it as a
reference -

It was develop to answer a specific need, scratch a personal itch, if you
will, and was probably never designed for mass mainline consumption and
it shows.

At the same time its code doing something similar in spirit to what we aim to
and has real word users. We would be foolish to ignore it.

So, a good reference (for the good and bad), not merge request. Right Chris? :-)

Gilad

--
Gilad Ben-Yossef
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gilad@xxxxxxxxxxxxx
Israel Cell: +972-52-8260388
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"If you take a class in large-scale robotics, can you end up in a
situation where the homework eats your dog?"
 -- Jean-Baptiste Queru
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