I encourage you to find some evidence showing that Konrad's assumption is mistaken, then.
Sam On Mon, Oct 21, 2013 at 2:38 PM, Matthias Felleisen <matth...@ccs.neu.edu> wrote: > > WIth respect, I think this shows nothing :-) > > > > On Oct 21, 2013, at 2:35 PM, Sam Tobin-Hochstadt <sa...@cs.indiana.edu> wrote: > >> On Mon, Oct 21, 2013 at 12:47 PM, Matthias Felleisen >> <matth...@ccs.neu.edu> wrote: >>> >>> In general, it is a mistaken assumption however that even in a >>> 'managed' language -- such as Java or Racket -- mutation is still >>> faster than de/allocation of short-lived data structures. If you >>> choose to go with 'managed' language, you need to adapt your >>> programming style to the new context. >> >> Sadly, this assumption is often right for Racket today, even though we >> have a pretty good allocator. Here's a simple benchmark: >> https://gist.github.com/samth/7088570 >> >> This just passes multiple arguments between two functions in three >> ways: with a cons, with multiple values, and by mutating an mcons >> (plus a direct version with two local variables). In all cases, it's >> as fast as I can make it, using unsafe operations where appropriate. >> >> Here are some representative timings: >> >> [samth@huor:~/sw/plt/racket/collects/racket/match (master) plt] r >> /tmp/bench.rkt >> 'direct >> cpu time: 40 real time: 44 gc time: 0 >> 'cons >> cpu time: 72 real time: 73 gc time: 12 >> 'values >> cpu time: 192 real time: 191 gc time: 0 >> 'mcons >> cpu time: 48 real time: 51 gc time: 0 >> >> Direct is always fastest, multiple values are very slow, and cons is >> always slower than mcons. Even if we ignore GC time, the functional >> version is still always slower. >> >> Sam > ____________________ Racket Users list: http://lists.racket-lang.org/users
