[GRLUG] FYI - old mysql and new gear

[Michael Mol]

On Thu, Sep 22, 2011 at 2:37 PM, Bob Kline <bob.kline at gmail.com> wrote:
> Affinity is something like tendency.
> The scheduler will do what you ask
> "as long as practical for performance
> reasons."

That's not the way it works on Windows. It would surprise me greatly
if that were the way it worked on Linux. On Windows, affinity is a
bitmask saying, "this process (or thread) is allowed to run on these
CPUs". Not quite the same thing as "hey, run on these cores as long as
it's convenient."

Without any other instruction, Linux's scheduler already pins threads
to individual cores until something needs that core more (such as an
interrupt tied to that core). If I run a single process that spins a
core at 100%, I see it stick to a single core for a long, long time,
and then I see it bounce to a different core, and hang out there for a
long, long time.


-- 
:wq

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