On Thu, Jun 21, 2007 at 08:18:23AM -0400, Brandon S. Allbery KF8NH wrote:
On Jun 21, 2007, at 6:40 , Andrea Rossato wrote:
I have this very simple program that executes an external program, reads its output and prints it (the program is "date"). The readings is done with pipes.
The problem is that memory usage constantly increases over time. Profiling does not show garbage collection of any sort.
Huh. Thank you; I'd observed that behavior in one of my programs but hadn't sat down to figure out why yet, mostly because I have a workaround: if you cap the heap (+RTS -M...) it *does* do GC.
Which makes it sound like something I don't know how to debug. :/
well, I followed Dougal's suggestion and riduced the program into pieces. I'm also testing the difference of runProcess and runInteractiveProcess. The first seems better but I need some more test. In the first case pipes2Handles gets 80.4% alloc. In the second is runRunIntProcess to get 88%. Results are pretty much the same after all. Now I'm going to profile for memory usage: I've seen that some GC happens if you are patient enough. Thanks for your kind attention. Andrea This is the code broken up: module Main where import System.Process import System.Posix.IO import System.IO import Control.Concurrent readOutput rh = do str <- hGetLine rh return str mkPipe = do (r,w) <- createPipe return (r,w) pipes2Handles r w = do wh <- fdToHandle w rh <- fdToHandle r return (rh,wh) runRunProcess wh c = do p <- runProcess c [] Nothing Nothing Nothing (Just wh) (Just wh) return p closeHandle rh wh = do hClose wh hClose rh runWithRunProcess c = do (r,w) <- mkPipe (rh,wh) <- pipes2Handles r w p <- runRunProcess wh c exit <- waitForProcess p str <- readOutput rh closeHandle wh rh putStrLn str threadDelay $ 100000 * 1 runWithRunProcess c runRunIntProcess c = do (sin,sout,serr,p) <- runInteractiveProcess c [] Nothing Nothing return $! (sin,sout,serr,p) cHandles i o e = do hClose i hClose o hClose e runWithRunIntProcess c = do (i,o,e,p) <- runRunIntProcess c exit <- waitForProcess p str <- readOutput o cHandles i o e putStrLn str threadDelay $ 100000 * 1 runWithRunIntProcess c main' = runWithRunProcess "date" main = runWithRunIntProcess "date"