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Re: usage of vyukov's mpsc queue

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dvyukov@google.com wrote:
> 
> On Wednesday, September 21, 2011 9:33:42 PM UTC+4, Alexander Terekhov wrote:
> > Dmitriy Vyukov wrote:
> > >
> > > Since you are doing signaling (SetEvent) after each push, I think you
> > > don't need anything special for it to work.
> > > However of course you need correct memory fences in the queue
> > > algorithm itself, that is I think as follows:
> > >
> > > void mpscq_push(mpscq_t* self, mpscq_node_t* n)
> > > {
> > >     n->next = 0;
> > >     mpscq_node_t* prev = XCHG(&self->head, n); // ACQUIRE_RELEASE
> >
> > "// ACQUIRE" (without _RELEASE) is sufficient here.
> >
> > But XCHG(...) can be totally relaxed with respect to memory barriers if
> > implemented as load-reserve/store-conditional or CAS loop (making
> > subsequent stores control-dependent).
> 
> In my model there is no such thing as "control-dependent", 
> each acquire simply must pair with release :)
> But I am curious about your model, how is n->next=0 prevented 
> from sinking below XCHG (which would be a disaster)? 
> It seems that even a compiler can easily do that.

My mistake. The XCHG's store is not control dependent on 
n->next = 0 and hence must have either release or sink-store 
(relaxed release affecting only preceding stores) label.

regards,
alexander.

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Thread

usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-20 06:55 -0700
  Re: usage of vyukov's mpsc queue Joshua Maurice <joshuamaurice@gmail.com> - 2011-09-20 17:19 -0700
    Re: usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-20 18:35 -0700
      Re: usage of vyukov's mpsc queue Ephraim Sinowitz <ephisinowitz@yahoo.com> - 2011-09-21 06:42 -0400
  Re: usage of vyukov's mpsc queue Joshua Maurice <joshuamaurice@gmail.com> - 2011-09-21 00:26 -0700
  Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 12:19 +0200
    Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 12:34 +0200
    Re: usage of vyukov's mpsc queue Ephi Sinowitz <ephisinowitz@yahoo.com> - 2011-09-21 06:58 -0400
      Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 14:02 +0200
        Re: usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-21 06:08 -0700
          Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 15:18 +0200
            Re: usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-21 06:56 -0700
              Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 17:06 +0200
                Re: usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-21 09:16 -0700
                Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 18:20 +0200
  Re: usage of vyukov's mpsc queue Dmitriy Vyukov <dvyukov@gmail.com> - 2011-09-21 09:58 -0700
    Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-09-21 19:33 +0200
      Re: usage of vyukov's mpsc queue dvyukov@google.com - 2011-10-02 04:13 -0700
        Re: usage of vyukov's mpsc queue Alexander Terekhov <terekhov@web.de> - 2011-10-04 12:15 +0200
    Re: usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-21 11:04 -0700
      Re: usage of vyukov's mpsc queue Ephi Sinowitz <esinowitz.public@gmail.com> - 2011-09-21 11:17 -0700
      Re: usage of vyukov's mpsc queue "Chris M. Thomasson" <cristom@charter.net> - 2011-09-24 22:44 -0700

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