On 12/23/09, Jon Harrop
And your results above indicate that the fastest imperative heap is over 3x faster than the fastest functional heap?
It's saying that (1) Using an imprecise an inefficient-relative-to-a-accurate-GC-that-doesn't- have-to-assume-the-entire-memory-space-is-live-then-find-what's-dead is a recipe for inefficiency. (2) And (1) even more so when you're comparing it to the same language with manual memory management and zero GC overhead. (from here on out I disregard the C numbers (i like C, too)) (3) So now, it's saying that (given this sample, yada yada) among languages where this comparison is possible (i.e. the mutable version still has the GC running) the functional version is on average 1.8 times slower. ghci> ((126/70) + (290/150) + (1895/1123)) / 3 1.8069258929454834 Matt
On Tuesday 16 June 2009 23:50:45 Richard O'Keefe wrote:
I've now done some benchmarks myself in C, Java, and Smalltalk, comparing "imperative" versions of leftist heaps with "functional" ones. For what it's worth, on a 2.16GHz Intel Core 2 Duo Mac, the coefficient in front of the log(n) part was
C Java ST(A) ST(B) "Imperative" 40 70 150 1123 "Functional" 240 126 290 1895
where ST(A) was a native-code Smalltalk and ST(B) a byte-code one. The C/Functional case used the Boehm collector, untuned. Times are in nanoseconds. Values of n ranged from 2 to 100; the correspondent was saying that small sizes were important.
It seems that a factor of 2 for *this* problem is credible; a factor of 10 is not.