Re: [Gems-users] Performance evaluation of CMP with Ruby and Opal

["Liqun Cheng" <liqun.cheng@xxxxxxxxx>]

Just my 2 cents.

1. The simulation is very very slow and it seems impossible to run the entire benchmark. 10 million cycles cost me more than one hour. Although I can specify warm up length, it is best to cover the entire life span of the benchmark. Has anyone tried to use a sampling approach? I guess it's OK to wait on the completion of the entire benchmark when producing final performance numbers, but it certainly is a pain whenever there is modification to the code and we want to see how it affects the performance. GEMS users, how do you handle this problem?

Most studies use Opal only in the sensitivity analysis, say run for 100M instructions. You might consider use the techniques in SMARTS. I vaguely remember CMU folks have released this in SimFlex.

2. Exactly what performance number should I look at to compare two systems, when both Opal and Ruby are used. I saw on FAQ that one should use Ruby_cycles  to measure the runtime of the simulated system. But when I let Opal run the same number of cycles, shouldn't Ruby_cycles be the same for both? If not, why?

Opal shows  how  many  instructions graduated, not cycles.

Liqun

I appreciate your comments!

 

Thanks,

Lei

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