Thanks for all the attention Robby, and I am glad that I could help find some improvement space.
The sad part is that for the new loop there is an increase of about 100% in the processing time, I guess it is because of the efficiency provided by the in-vector inside the for. Cool list, as usual. On 12/20/2010 07:48 PM, Robby Findler wrote: > On Mon, Dec 20, 2010 at 1:02 PM, Eduardo Bellani <ebell...@gmail.com> wrote: >> My output to your suggested approach is >> >> GC [minor] at 1514740 bytes; 818464 collected in 4 msec >> GC [minor] at 2142928 bytes; 678980 collected in 4 msec >> GC [minor] at 4424700 bytes; 1509104 collected in 12 msec >> GC [minor] at 4999304 bytes; 614508 collected in 16 msec >> GC [minor] at 8337384 bytes; 1957728 collected in 20 msec >> GC [minor] at 10529324 bytes; 1709172 collected in 24 msec >> GC [minor] at 14245196 bytes; 2815768 collected in 28 msec >> GC [minor] at 19109972 bytes; 4515808 collected in 48 msec >> GC [minor] at 20287336 bytes; 4153060 collected in 32 msec >> GC [minor] at 416134292 bytes; -27108 collected in 1652 msec >> cpu time: 2660 real time: 2657 gc time: 1652 >> cpu time: 1000 real time: 1001 gc time: 0 >> 2 success(es) 0 failure(s) 0 error(s) 2 test(s) run >> 0 >> >> Which for me is not helpful. Any more suggestions? > > I get the following line of output (in the development version): > > future: 0 waiting for runtime at 1292881244093.291016: values > > and, sure enough, looking at the expansion of the loop: > > (for ([i (in-vector some-data)]) i) > > I see that it uses multiple values which, I believe are not safe for futures. > > I believe that this is a recent change and hopefully whoever did it > will fix it (I'll post separately about this). But in the meantime, > the program below produces these two 'time' lines for me: > > cpu time: 1586 real time: 845 gc time: 0 > cpu time: 1596 real time: 1595 gc time: 0 > > which indicates that the two loops happened in parallel in the first > case and not in the second. > > Robby > > #lang racket > > (require racket/future > rackunit > rackunit/text-ui > racket/fixnum) > > (define DATA (make-vector 99999999 'datum)) > > (define-test-suite read-from-shared > (test-suite "with futures" > (check-equal? > (time (let ([f (future (λ () (read-data DATA)))]) > (read-data DATA) > (touch f))) > (void))) > > (test-suite "no futures" > (check-equal? > (time (read-data DATA) > (read-data DATA)) > (void)))) > > (define (read-data some-data) > (let ([end (vector-length some-data)]) > (let loop ([i 0]) > (unless (fx= i end) > (vector-ref some-data i) > (loop (fx+ i 1)))))) > > (collect-garbage) (collect-garbage) > (run-tests read-from-shared) -- Eduardo Bellani omnia mutantur, nihil interit. _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
