Bulat Ziganshin wrote:
Hello Andrew,
Wednesday, September 16, 2009, 11:31:22 PM, you wrote:
If you're going to use par, it doesn't really matter how many sparks you
create. You just need to avoid creating millions of really tiny sparks.
You could create, say, eight and let GHC figure out the rest itself...
since these are green threads, 1 millisecond sparks should be
acceptable and may be even 1 microsecod too.
Of course, how many split seconds it takes depends on the speed of the
processor running it. ;-) But you probably don't want to spark, say, one
addition operation. (Unless perhaps you're adding *really huge*
arbitrary-precision integers or something.) Actually, it might be
interesting to benchmark where the balance tips; exactly how much work
you need to do for the spark overhead to be worth it. It's likely to
vary by GHC version though...
afair, overhead expenses
was significantly reduced in ghc 6.12, soon to be released
I've heard similar things. I think I even read a paper about it. (Those
GHC guys... always putting out such interesting papers! If it weren't
for them, I might actually get some work done...) If you wanted to
benchmark anything, it would seem prudent to wait for this. ;-)
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