Speeding up number conversions

[Mike Dillon]

We have an application that displays thousands of currency values on a page, using the "number_to_currency" converter. When profiling the view rendering time, I found that a large amount of time was spent in the number helper classes. One level deeper, a bunch of time was spent calling I18n.translate to retrieve format options that were the same for the entire page.

I think it would be nice to optimize these helpers to allow subclasses of NumberConverter to be reused. I spent 10 minutes modifying the converters to allow them to be called more than once with the same options. After that, I did a quick test using bench.rb from the attached diff and saw roughly a 10x improvement in speed:

$ bundle exec ./bench.rb 

Rehearsal ------------------------------------------------------

original delimited   3.110000   0.070000   3.180000 (  3.262467)

reused delimited     0.270000   0.010000   0.280000 (  0.284962)

original currency   13.140000   0.100000  13.240000 ( 13.395538)

reused currency      1.240000   0.020000   1.260000 (  1.276842)

-------------------------------------------- total: 17.960000sec

                         user     system      total        real

original delimited   2.820000   0.010000   2.830000 (  2.846727)

reused delimited     0.250000   0.010000   0.260000 (  0.265952)

original currency   12.870000   0.080000  12.950000 ( 13.020219)

reused currency      1.220000   0.020000   1.240000 (  1.241132)

Are these changes something the Rails Core team is amenable to pursuing? Should I open a PR with my changes and some additional tests?

Thanks!

-md