On Fri, Jul 03, 2015 at 04:06:45PM +0000, Baojun Wang wrote:
Full source code:
https://github.com/wangbj/haskell/blob/master/lcmsum.hs
I build the program with:
ghc -O2 --make -rtsopts -prof -auto-all lcmsum
and run it with:
echo -ne '5\n100\n1000\n10000\n100000\n1000000\n' | ./lcmsum +RTS -sstderr -p
I've tried use
``let !ret = (v1+(fromIntegral i) * (fromIntegral v)) in r'' instead, however it didn't make any difference per profiling. (both Array are Unboxed).
Correct, since they're unboxed forcing the thunk is done automatically. I'm puzzled. What output are you seeing and what were you expecting? I see "13 MB total memory in use". That doesn't sound like a lot when you are allocating two arrays of size 10^6. There's a lot of *allocation*, but not so much peak memory usage. I get the same result on GHC 7.6.3 and 7.8.4. My complete output: % ghc -O2 --make -rtsopts -prof -auto-all lcmsum [1 of 1] Compiling Main ( lcmsum.hs, lcmsum.o ) lcmsum.hs:48:9: Warning: In the use of `unsafeFreeze' (imported from Data.Array.IO, but defined in Data.Array.MArray): Deprecated: "Please import from Data.Array.Unsafe instead; This will be removed in the next release" lcmsum.hs:51:3: Warning: In the use of `unsafeFreeze' (imported from Data.Array.IO, but defined in Data.Array.MArray): Deprecated: "Please import from Data.Array.Unsafe instead; This will be removed in the next release" Linking lcmsum ... % echo -ne '5\n100\n1000\n10000\n100000\n1000000\n' | ./lcmsum +RTS -sstderr -p 152935099400 1529628080000 278320460000 277913417200000 277811686426000000 2,273,379,656 bytes allocated in the heap 233,104 bytes copied during GC 12,002,728 bytes maximum residency (3 sample(s)) 580,184 bytes maximum slop 13 MB total memory in use (0 MB lost due to fragmentation) Tot time (elapsed) Avg pause Max pause Gen 0 4350 colls, 0 par 0.02s 0.02s 0.0000s 0.0000s Gen 1 3 colls, 0 par 0.00s 0.00s 0.0003s 0.0005s INIT time 0.00s ( 0.00s elapsed) MUT time 2.66s ( 2.65s elapsed) GC time 0.02s ( 0.02s elapsed) RP time 0.00s ( 0.00s elapsed) PROF time 0.00s ( 0.00s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 2.67s ( 2.67s elapsed) %GC time 0.6% (0.6% elapsed) Alloc rate 856,218,428 bytes per MUT second Productivity 99.4% of total user, 99.5% of total elapsed