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wman | 7 Oct 05:54
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Re: newbie questions (read, etc., with Data.ByteString.Lazy.Char8)

just for the kicks i tried the new version of bytestring without -O2 and the results were even worse:

time Main1 < nums
real    0m40.092s
user    0m0.015s
sys     0m0.015s

time Main3 < nums
real    0m41.405s
user    0m0.015s
sys     0m0.015s

it got pwned even by this very naive ruby scipt (which, btw, chewed through some ~600 MB of memory ;-))

File.open("nums","r") do |f|
  puts((f.read.split.each {|x| x.to_i }).length)
end

time ruby nums.rb
real    0m21.609s
user    0m0.015s
sys     0m0.015s

so it probably can't be stressed enough: repeat "-O2"

and now seriously:

is there a reason why -O2 shouldn't be made the default (and allowing to turn off optimizations by -O0 perhaps) ?

On Tue, Oct 7, 2008 at 5:36 AM, wman <666wman <at> gmail.com> wrote:
new figures, after updating bytestring (0.9.0.1.1 -> 0.9.1.2) && using -O2

time Main < nums
real    0m2.531s

user    0m0.015s
sys     0m0.015s

time Main2 < nums
real    0m13.999s

user    0m0.015s
sys     0m0.015s

time Main3 < nums
real    0m2.796s

user    0m0.015s
sys     0m0.015s

thats more like it, even the unpacking didn't hurt so much.

the morals: "Thou shalt update your libraries" & "Thou shalt not forget to turn on optimizations" before bitching it's too slow ;-)))

thx


On Tue, Oct 7, 2008 at 5:19 AM, Don Stewart <dons <at> galois.com> wrote:
Hmm. How are you compiling it? Using bytestring 0.9.1.x ?

Should be fast,
   http://shootout.alioth.debian.org/gp4/benchmark.php?test=sumcol&lang=all

Assuming you're turning on optimisations ( ghc -O2 )

-- Don


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