> On Jan. 19, 2017, 10:18 p.m., Jason Lowe-Power wrote:
> > Does converting this to a class have any impact on performance?
> 
> Rekai Gonzalez Alberquilla wrote:
>     The honest reply is I do not know. The long reply is: I did differential 
> performance analysis between the base of the 5 patches and each of the 
> patches. The 2nd or 3rd had a 2% slowdown, because I changed the rename table 
> to use a hash_map, so it mapped regIds to physRegIds. There used to be an 
> extra patch that reverted that. After applying all of them, test runs had a 
> marginal speedup (as the use of regIds allows for some more static 
> optimisations). Satisfied with that result, I merged the patch that reverted 
> the change into the 'generalize the use of regIds' patch, and I did not look 
> further into it.
>     If you think individual impact must be assesed, I can do a performance 
> regression.

Sounds good. It seemed possible that the added vtable lookup multiple times per 
instruction could have caused a performance drop. But since you checked, and it 
doesn't, the compiler must be smarter than me!


- Jason


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On Jan. 26, 2017, 1:40 p.m., Rekai Gonzalez Alberquilla wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviews.gem5.org/r/3756/
> -----------------------------------------------------------
> 
> (Updated Jan. 26, 2017, 1:40 p.m.)
> 
> 
> Review request for Default.
> 
> 
> Repository: gem5
> 
> 
> Description
> -------
> 
> Changeset 11761:58decfdf9c7b
> ---------------------------
> cpu: Result refactoring
> 
> The Result union used to collect the result of an instruction is now a
> class of its own, with its constructor, and explicit casting methods for
> cleanliness.
> 
> This is also a stepping stone to have vector registers, and instructions
> that produce a vector register as output.
> 
> Change-Id: I6f40c11cb5e835d8b11f7804a4e967aff18025b9
> Reviewed-by: Andreas Sandberg <[email protected]>
> 
> 
> Diffs
> -----
> 
>   src/cpu/base_dyn_inst.hh 78ef8daecd81 
>   src/cpu/checker/cpu.hh 78ef8daecd81 
>   src/cpu/checker/cpu_impl.hh 78ef8daecd81 
>   src/cpu/inst_res.hh PRE-CREATION 
> 
> Diff: http://reviews.gem5.org/r/3756/diff/
> 
> 
> Testing
> -------
> 
> Builtin regressions
> 
> 
> Thanks,
> 
> Rekai Gonzalez Alberquilla
> 
>

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