Hello Duncan, Sunday, September 24, 2006, 12:22:38 AM, you wrote:
>> after program prints "40 mb allocated" look at Task Manager indication >> - it shows that two times more memory actually in use. it seems that >> problem is only with allocating memory buffers whose sizes are powers >> of 2 or very close - bug shows for bufsize = 4kb, 1mb or 4095, but not >> not for 4000 or 10^6 > The reason for this is that for larger objects ghc has an allocation > granularity of 4k. That is it always uses a multiple of 4k bytes. with 512k blocks it also allocates two times more data than requested. > However a byte array has some overhead: it needs one word for the heap > cell header and another for the length. So if you allocate a 4k byte > array then it uses 8k. So the trick is to allocate 4k - overhead. This > is what the Data.ByteString library does. thank you - it will be ok for my lib -- Best regards, Bulat mailto:[EMAIL PROTECTED] _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
