RFR (): JDK-8228503: Rename "rs_lengths" to "rs_length" in ergo code

[Per Liden]

Looks good!

/Per

On 7/25/19 3:55 PM, Thomas Schatzl wrote:
> Hi,
> 
>    can I have reviews for this change that (mechanically) changes all
> prediction related identifiers with the "rs_lengths" suffix to
> "rs_length"?
> 
> The reason is that all these values are not vectors like the plural-s
> suggests (and I think we use this naming style in other places), but
> contain a scalar (sum) value. Reading through the prediction code with
> this style is really annoying, given that the code later performs
> standard mathematical ops with single values on that:
> 
> E.g.
> double time_spent = predicted_rs_lengths * predict_cost_per_card();
> 
> Note that I understand that there is some reasoning for that as these
> variables contain the sum of differences, or the sum of remembered set
> "lengths" (for which we typically use "num_*_entries"/"num_*_cards" in
> other places); however due to way these are used (e.g. to predict the
> singular remembered set "length" of the entire young gen) I would
> prefer to remove the "s".
> 
> I am okay with keeping the "rs_length" as it is to me by far not as
> annoying, and I did so.
> 
> Alternatively I would suggest to add at least "sum" postfix to the
> names.
> 
> The change also fixes multiple similar pluralization like
> "_inc_recorded_rs_lengths_diffs".
> 
> There is some particular misnomer ("max_rs_length") that is going to be
> fixed in the next CR (JDK-8228504).
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8228503
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8228503/webrev/
> Testing:
> hs-tier1-3
> 
> Thanks,
>    Thomas
>