spinlocks

jschopp at austin.ibm.com jschopp at austin.ibm.com
Tue Jan 6 05:07:45 EST 2004


Based on past experience putting or instructins in locking routines I
think it is worth doing.  The performance hit isn't from the execution of
the instructions but from the extra space they take up.  It is not a huge
difference, but it is measurable.  Spinlocks are called enough that
anything measurable should be optimized.  Amdahl's law and all.

On Mon, 5 Jan 2004, David Boutcher wrote:
> Could, though the HMT_* instructions just map to "or 0,0,0", "or 1,1,1",
> etc, which are otherwise no-ops.  The processor should do those in one
> cycle, or even less.
>
> Dave Boutcher
> IBM Linux Technology Center
>
>


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