Hi Peter, Source code: import System.IO import System.Posix main = do putStrLn "Waiting for 5 seconds." sleep 5 -- doesn't sleep at all putStrLn "Done." OS: Mac OS X 10.5 Compile command: ghc --threaded testsleep.hs If I remove --threaded, then it does sleep. Thanks, -John On Tue, Feb 10, 2009 at 8:59 AM, Peter Verswyvelen wrote:

Hi John, Which sleep are you using? From which module? Can you show the full source with import statements?

Cheers, Peter

2009/2/9 John Ky

...

Hi Haskell Cafe,

I wrote very short program to sleep for 5 seconds compiled with the -threaded option in ghc on the Mac OS X 1.5.

I am finding that using the sleep function doesn't sleep at all, whereas using threadDelay does:

main = do putStrLn "Waiting for 5 seconds." threadDelay 5000000 -- works putStrLn "Done."

main = do putStrLn "Waiting for 5 seconds." sleep 5 -- doesn't sleep at all putStrLn "Done."

Anybody know what's happening?

Thanks

-John

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The POSIX sleep function is defined as: sleep() makes the current process sleep until seconds seconds have elapsed or a signal arrives which is not ignored. Sounds like a signal is arriving that is interrupting the sleep. -Corey O'Connor 2009/2/9 John Ky :

Hi Peter,

Source code: import System.IO import System.Posix

main = do putStrLn "Waiting for 5 seconds." sleep 5 -- doesn't sleep at all putStrLn "Done."

OS: Mac OS X 10.5

Compile command: ghc --threaded testsleep.hs

If I remove --threaded, then it does sleep.

Thanks,

-John

On Tue, Feb 10, 2009 at 8:59 AM, Peter Verswyvelen wrote:

...

Hi John, Which sleep are you using? From which module? Can you show the full source with import statements? Cheers, Peter 2009/2/9 John Ky

...

Hi Haskell Cafe,

I wrote very short program to sleep for 5 seconds compiled with the -threaded option in ghc on the Mac OS X 1.5.

I am finding that using the sleep function doesn't sleep at all, whereas using threadDelay does:

main = do putStrLn "Waiting for 5 seconds." threadDelay 5000000 -- works putStrLn "Done."

main = do putStrLn "Waiting for 5 seconds." sleep 5 -- doesn't sleep at all putStrLn "Done."

Anybody know what's happening?

Thanks

-John

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On Tue, 2009-02-10 at 09:57 -0800, Corey O'Connor wrote:

The POSIX sleep function is defined as: sleep() makes the current process sleep until seconds seconds have elapsed or a signal arrives which is not ignored.

Sounds like a signal is arriving that is interrupting the sleep.

-Corey O'Connor

I tested this when testing the original code; sleep reports that the signal received is 5 (SIGTRAP). However, the following code does not work:

import System.Posix

main = do putStrLn "Waiting for 5 seconds." print sigTRAP blockSignals $ addSignal sigTRAP emptySignalSet signal <- sleep 5 print signal putStrLn "Done."

This, on the other (strange) hand, does:

import System.Posix

main = do putStrLn "Waiting for 5 seconds." blockSignals fullSignalSet signal <- sleep 5 print signal putStrLn "Done."

- George

On Wed, 2009-02-11 at 00:05 +0100, Manlio Perillo wrote:

John Ky ha scritto:

...

Hi Haskell Cafe,

I wrote very short program to sleep for 5 seconds compiled with the -threaded option in ghc on the Mac OS X 1.5.

I am finding that using the sleep function doesn't sleep at all, whereas using threadDelay does:

[...] main = do putStrLn "Waiting for 5 seconds." sleep 5 -- doesn't sleep at all putStrLn "Done."

Anybody know what's happening?

Here is a syscal trace, on Linux: http://hpaste.org/fastcgi/hpaste.fcgi/view?id=1332#a1332

The interesting part: write(1, "Waiting for 5 seconds.\n"..., 23) = 23 rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0 rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 nanosleep({5, 0}, 0xbf85f5cc) = ? ERESTART_RESTARTBLOCK (To be restarted) --- SIGVTALRM (Virtual timer expired) @ 0 (0) --- sigreturn() = ? (mask now []) write(1, "5\n"..., 2) = 2

So, it seems nanosleep get interruped by a signal.

This works:

import System.Posix

main = do putStrLn "Waiting for 5 seconds." blockSignals $ addSignal sigVTALRM emptySignalSet sleep 5 putStrLn "Done."

So (see my earlier email) `sleep` is lying about what interrupts it :) - George

Also attached is a diff for strace between non-threaded and threaded.

George Pollard ha scritto:

[...]

...

So, it seems nanosleep get interruped by a signal.

This works:

...

import System.Posix

main = do putStrLn "Waiting for 5 seconds." blockSignals $ addSignal sigVTALRM emptySignalSet sleep 5 putStrLn "Done."

So (see my earlier email) `sleep` is lying about what interrupts it :)

- George

A possibly better solution is: sleep' :: Int -> IO Int sleep' n = do n' <- sleep n if n' == 0 then return 0 else sleep' n' From the trace, I see that nanosleep is being called 17 times here. Another solution is to set RTS flag: ./bug_sleep +RTS -V0 -RTS What strange is that the timer is created in non threaded RTS, too, but sleep is interrupted only with the threaded RTS. This may be caused by an "incorrect" execution of a foreign function marked safe. Regards Manlio