Re: [Gems-users] regd. event queue

[Dan Gibson <degibson@xxxxxxxx>]

Simultaneous was the implementation goal for same-cycle events -- but 
since Ruby is implemented sequentially the events, of course, actually 
execute sequentially. Events in the "same cycle" are technically 
unordered, though in practice they are ordered by the implementation of 
the priority heap used by EventQueue.[Ch].
Adding magic instructions and/or callbacks will affect the number of 
observed Ruby_cycles, in the following ways:
1) Addition of a sethi instruction (eg. magic call) changes the 
execution path ( a sethi takes at least a cycle to execute, after all), 
i-cache behaviour, etc., and could (very rarely) cause more interesting 
effects (eg. perhaps by adding sethi instructions a particular 
PC-relative branch path becomes impossible to express).
2) Magic instructions/callbacks definitely can impact the behaviour of 
Ruby (depending on what your code does in response to them), which can 
in turn affect the observed cycle count.
3) Rarely, as a corollary of #1, addition of instructions can affect 
entire dynamic executions due to changes in the order of synchronization 
events.
Regards,
Dan

Dave Z. wrote:
> Hello,
>
> Does the event queue trigger simultaneous events? Or
> everything takes place sequentially?
>
> Would the addition of magic instructions and callbacks
> increase Ruby cycles?
>
> Thanks,
>
> Dave
>
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