And, interestingly enough, suddenly the AMD FX-8350 beats the Intel Core i7 3770K, when before it was very very much not so. So for some reason, this bug was tickled more dramatically on AMD multicore processors than on Intel ones.
On Tue, Dec 11, 2012 at 2:54 PM, Wm. Josiah Erikson <wmjos...@gmail.com>wrote: > OK WOW. You hit the nail on the head. It's "reverse" being called in a > pmap that does it. When I redefine my own version of reverse (I totally > cheated and just stole this) like this: > > (defn reverse-recursively [coll] > (loop [[r & more :as all] (seq coll) > acc '()] > (if all > (recur more (cons r acc)) > acc))) > > > > I speed it up from, get this, 4:32 to 0:25. Yeah. > > In case anybody's curious, pmap and pmapall show identical performance in > this case. > > Wow. > > -Josiah > > > On Tue, Dec 11, 2012 at 1:06 PM, Marshall Bockrath-Vandegrift < > llas...@gmail.com> wrote: > >> Lee Spector <lspec...@hampshire.edu> writes: >> >> > If the application does lots of "list processing" but does so with a >> > mix of Clojure list and sequence manipulation functions, then one >> > would have to write private, list/cons-only versions of all of these >> > things? That is -- overstating it a bit, to be sure, but perhaps not >> > entirely unfairly -- re-implement Clojure's Lisp? >> >> I just did a quick look over clojure/core.clj, and `reverse` is the only >> function which stood out to me as hitting the most pathological case. >> Every other `conj` loop over a user-provided datastructure is `conj`ing >> into an explicit non-list/`Cons` type. >> >> So I think if you replace your calls to `reverse` and any `conj` loops >> you have in your own code, you should see a perfectly reasonable >> speedup. >> >> -Marshall >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clojure@googlegroups.com >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+unsubscr...@googlegroups.com >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
