ramnivas April 1 2015  
@sjrd as an additinal data point to @matthughes, here is output from my fastOptJS run
 https://gist.github.com/ramnivas/723b816bef73a4592a7f
The change I made was a trivial one ("foo" -> "fooo")

sjrd April 1 2015  
Seems you would also benefit from an incremental linker.

ramnivas April 1 2015  
That will be awesome!

japgolly April 1 2015  
Me too  This is my output from after just adding a newline to a file:
[debug] Linker: Read info: 21185 us
[debug] Linker: Compute reachability: 381551 us
[debug] Linker: Assemble LinkedClasses: 1576527 us
[debug] Linker: cache stats: reused: 13811 -- invalidated: 6 -- trees read: 6
[debug] Linker: 1983960 us
[debug] Inc. optimizer: Batch mode: false
[debug] Inc. optimizer: Incremental part: 18653 us
[debug] Inc. optimizer: Optimizing 6 methods.
[debug] Inc. optimizer: Optimizer part: 1425 us
[debug] Inc. optimizer: 34441 us
[debug] Refiner: Compute reachability: 289414 us
[debug] Refiner: Assemble LinkedClasses: 18914 us
[debug] Refiner: 308436 us
[debug] Emitter: Class tree cache stats: reused: 3125 -- invalidated: 5
[debug] Emitter: Method tree cache stats: resued: 14569 -- invalidated: 6
[debug] Emitter (write output): 832415 us
@ramnivas Your times are massive! How large is your codebase mate?

ramnivas April 1 2015  
@japgolly Only about 100 *.scala files (spread over 6 subprojects)
This is for the web part only
@japgolly How large is your codebase, mate?

japgolly April 1 2015  
Interesting. My SJS project is 131 files and 9762 LoC.
(Plus a bunch of lib deps like scalaz, scalajs-react, monocle, etc etc)
Your linker takes 80% more time than mine.
What machine are you running on?

ramnivas April 1 2015  
LoC for my project is at 3820
Macbook Pro late model 2.5GHz i7, 16 MB RAM, SSD

japgolly April 1 2015  
My env = Arch Linux, i7-3770 CPU @ 3.40GHz (8 core), 16gb ram, SSDs
Cool, machine difference probably explains why your's takes longer

ramnivas April 1 2015  
Right

japgolly April 1 2015  
It will be awesome if SJS gets an incremental linker. Saving 2, 3 seconds makes a big difference when you change something small and just want to refresh the browser.

ramnivas April 1 2015  
I definitely noticed that machine difference is a significant factor. On another i5 machine, it takes about twice as much
Right. And I like many have tendency to make many many small changes, so it quickly adds up.
More important than elapsed time is breaking of the change code-see the effect rhythm