Re: [Gems-users] ruby cycles compare with simics cycles

[mehmetderin.harmanci@xxxxxxx]

 Hello,

 Probably, in your rubyconfig.defaults file (or in your command line setting
 of parameters) you have line such as

    SIMICS_RUBY_MULTIPLIER: 2

 Change it to

    SIMICS_RUBY_MULTIPLIER: 1


 then you should have the Simics and Ruby cycles the same. GEMS authors
 will tell you better than I do, but if I understood well form the code
 one Simics passes a memory access to Ruby, Ruby stores the corresponding
 messages resulting from the access in its Event queue and return the control
 to Simics and Simics actually wakes Ruby cycle by cycle (these cycles
 are the cycles of Ruby Event Queue) until Ruby returns a stall value and
 unstall Simics functionality. So each time Ruby return control to
 Simics, it tells Simics to count SIMICS_RUBY_MULTIPLIER cycles. Thus, each
 cycle of Ruby Event Queue corresponds to  SIMICS_RUBY_MULTIPLIER Simics
 cycles. As a result setting this parameter to 1,you will have both cycles
 counting the same.

 I hope this is a correct explanation and will help to solve your problem.


      Derin Harmanci


Quoting xiaox@xxxxxxxxxx:

> hi,
>
> I want to use the ruby_cycles as my performance metric. However, I observe
> that
> ruby_cycles is different from the number of cycles I counted through Simics?
> Why is that? I suppose ruby always return its latency to Simics. So I should
> have the same number of cycles on both sides. And the simics cycles is
> almost
> twice as the ruby cycles. Can anyone explain to me how ruby counts its
> cycles?
>
> many thanks,
>
> btw, I am using gems1.1 with simics-2.0.28
>
>
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