Re: [Gems-users] Instructions executed

[Mike Marty <mikem@xxxxxxxxxxx>]

There is randomness injected into the runs to account for non-determinism
found in multithreaded workloads.

This is found in $gems/ruby/config/RubyConfig.h (memoryResponseLatency())

Could this be why your # of instructions executed is different?

--Mike

> Hello All,
>
> I'm having trouble making an  accurate comparison between two coherence
> models both based on MOESI_CMP_directory with Ruby. I am using a 16-core
> CMP and my initial approach was to run the same benchmark with the two
> models for a specific number of instructions (c 50000000) and compare
> the total ruby cycles elapsed. This didn't work because the 2 runs
> resulted in a different number of total instructions executed.
>
> Another method I tried was to have a magic instruction at the beginning
> and end of the benchmark so that I can track the total ruby cycles taken
> to complete the entire benchmark. Then again, the total instructions
> executed differed (which did not make sense to me at all, especially
> since both start from the same checkpoint).
>
> So how would I go about making a fair comparison of the two models? Is
> there any way you can make simics execute a certain number of total
> instructions or make ruby execute a certain number of total cycles?
>
> Thanks much.
>
> -Vivek
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