Thanks Guys, Not only did I not run optimizations, I misread the profile. It looks like it was an imaginary problem from the beginning. I guess I should go through all the profiling documentation more carefully. Jeff On Tue, Feb 17, 2009 at 2:46 PM, Bernie Pope wrote:

On 17/02/2009, at 3:56 PM, Jeff Douglas wrote:

...

Hello All,

The kind people at #haskell suggested I come to haskell-cafe for questions about haskell performance issues. I'm new to haskell, and I'm having a hard time understanding how to deal with memory leaks.

I've been playing with some network server examples and I noticed with each new connection, the memory footprint increases by about 7k However, the leaks don't seem to have anything to do with the networking code. Actually I get a huge leak just from using using 'forever'.

...

import Control.Monad import System.IO

main = forever $ putStrLn "hi"

When I run it for a few seconds with profiling...

...

total time = 0.36 secs (18 ticks @ 20 ms) total alloc = 54,423,396 bytes (excludes profiling overheads)

Can this be right?

I don't think there should be a space leak in the code you posted.

On my mac, OS X 10.5.6, GHC version 6.8.3, it appears to run in constant space with or without optimisation.

GHCi seems to gobble a little bit of memory (but that could be incidental).

My terminal application does gobble memory for a while (and then frees it), but that is presumably because it is hammering the buffer (and it nearly sets my lap on fire when running).

Perhaps you could post more details about how it is compiled, and what versions of things are being used.

How are you detecting the leak (via top?).

Cheers, Bernie.

I'd love to. I'm thinking of starting a blog once I get more experience and familiarity with the language. Jeff On Wed, Feb 18, 2009 at 6:13 PM, Magnus Therning wrote:

On Tue, Feb 17, 2009 at 5:53 AM, Jeff Douglas wrote:

...

Thanks Guys,

Not only did I not run optimizations, I misread the profile. It looks like it was an imaginary problem from the beginning. I guess I should go through all the profiling documentation more carefully.

Please share what you find in some way (mail/blog/anything). It'll help me avoid making the same mistakes once I get around to writing something in Haskell where I have to care about resources :-)

/M

-- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe