rails/rails — pull request #8559 by mshytikov (2012-12-19 14:40:32+00:00)
Title: attempt to fix slow runner name method

Replacement for https://github.com/rails/rails/pull/#4280

Updated to use ThreadSafe::Cache

Using https://gist.github.com/2710476

```ruby
Running benchmark with current working tree
Checkout HEAD^
Running benchmark with HEAD^
Checkout to previous HEAD again

user system total real
-----------------------------------------------set_callback
After patch: 0.030000 0.000000 0.030000 ( 0.028368)
Before patch: 0.050000 0.010000 0.060000 ( 0.045907)
Improvement: 38%

-------------------------------------------define_callbacks
After patch: 0.030000 0.000000 0.030000 ( 0.036034)
Before patch: 0.030000 0.000000 0.030000 ( 0.035713)

----------------------------------------------run_callbacks
After patch: 0.010000 0.000000 0.010000 ( 0.007374)
Before patch: 0.010000 0.000000 0.010000 ( 0.011215)
Improvement: 34%

----------------------------------------------skip_callback
After patch: 0.040000 0.000000 0.040000 ( 0.044974)
Before patch: 0.050000 0.000000 0.050000 ( 0.052612)
Improvement: 15%
```