John Goerzen wrote:
Simon Marlow wrote:
John Goerzen wrote:
Brian B wrote:
Hi Bulat,
My contribution to the survey: I've used forkProcess to daemonize
a ghc program inside the haskell fuse bindings:
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HFuse
http://code.haskell.org/hfuse/System/Fuse.hsc
If removing the non-threaded RTS would break forkProcess entirely,
these bindings would have to do something different. The issue: users
of the FUSE C api will get daemonized using daemon(2); it'd be
nice if GHC fuse programs could behave similarly.
I also use forkProcess extensively: in HSH, for instance, which is used
by hpodder, twidge, and a host of other tools. Removing the ability to
use forkProcess removes the ability to write a Unix shell in Haskell, or
to do anything shell-like, or anything even mildly advanced involving
piping, file descriptors, and the like. I would see it as a significant
regression.
Have you tried those apps with the threaded RTS? I'd be interested to
know whether they work as expected.
I have, and it didn't work well. But it's been awhile, and I can't tell
you anymore what version of GHC or what exactly the problem was. I was
most certainly 6.8 or older. Once 6.10 hits Debian, I could test again
there. But see below...
I'm not suggesting we remove the non-threaded RTS, however perhaps
there's an argument for making -threaded the default. After all, that's
what you get with GHCi by default right now.
That's probably an OK solution.
I would also add: does the threaded RTS support all platforms? For
instance, GHC runs on my Alpha and on AIX, unregisterised. ghci doesn't
run there, but GHC does. If you drop the non-threaded RTS, does that
mean that GHC doesn't work there at all?
If those platforms support threads, there's no reason why the threaded
RTS shouldn't work there. Also, GHCi should work on all platforms (even
unregisterised) these days, including the FFI if there's support in
libffi for that platform.
However, if if the threaded RTS doesn't work on a platform for some
reason, that doesn't prevent us just falling back to the non-threaded
RTS for that platform. Most things will still work.
The System.Process calls, last I checked (in 6.8.x) were both too buggy
to use for complex tasks, and too inadequate for some (though the
adequacy has been improving.)
If there's bugginess we need to get it fixed - please report those bugs!
Already done:
http://hackage.haskell.org/trac/ghc/ticket/1780
(still open since Nov 2007)
That one is closed - fixed in 6.8.3 I think.
There was also a thread here regarding problems with the threaded RTS:
http://www.mail-archive.com/[email protected]/msg11573.html
Not sure if that has been fixed, or was an error on my part, but see
your reply at:
http://www.mail-archive.com/[email protected]/msg11585.html
I did make a ticket for that:
http://hackage.haskell.org/trac/ghc/ticket/1185
That should be fixable - I'll put it on the current milestone.
Cheers,
Simon
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