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Spinlock and lockfree and waitfree...

Cross-posted to 2 groups.

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Hello,

I have come to an interresting subject, and you have
to be smart to understand it more...

If you take a look at the following FIFO queue that is
waitfree on the push() side and lockfree on the pop()
side, here it's:

http://pastebin.com/f72cc3cc1

as i said before , there is a weaknesses with this FIFO queue, first
the lockfree side on the pop() is not FIFO fair , so it's not 
starvation-free on the pop() side, and there is a second weakness:
it doesn't minimizes the cache-coherence traffic ,
but there is also a third  weakness with this algorithm: since
you can not use an exponential backoff on the waitfree pop() side
you can not make it 4 times or 6 times faster under contention on the 
push() side,
the Spinlock() with an exponential backoff mechanism on the pop()
and the push() is 4 times to 6 times faster than the lockfree
version and the waitfree version without a backoff mechanism and
i have just explain it to you,
but you can add an exponential backoff on the pop() lockfree side of
this FIFO que,
and this will make it 6 times faster under contention on the pop() side.


So in my opinion , since the Spinlock with an exponential backoff is
6 times faster under contention ,  so the risk of a stavartion will
be lowered, and since it minimizes the cache-coherence traffic, so this 
will make the Spinlock with an exponential backoff
a better alternative if you want better speed and to minimize 
cache-coherence traffic.



Thank you,
Amine Moulay Ramdane.

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Spinlock and lockfree and waitfree... aminer <aminer@toto.net> - 2013-10-15 20:03 -0700
  Re: Spinlock and lockfree and waitfree... aminer <aminer@toto.net> - 2013-10-15 21:35 -0700
  Re: Spinlock and lockfree and waitfree... "Chris M. Thomasson" <no@spam.invalid> - 2013-10-17 17:10 -0700

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