-threaded

[Simon Marlow]

Christian Maeder wrote:
> Simon Marlow schrieb:
> 
>>Gregory Wright wrote:
>>
>>>Both 6.4.2 and HEAD show the problem on OS X.   It can be avoided by
>>>disabling the threaded rts, but that is not acceptable solution.
>>
>>This is a good datapoint, because it probably rules out much of the
>>threaded RTS code in the RTS itself, which has changed significantly
>>between 6.4.x and HEAD.
> 
> 
> Could you summarize the advantages (or need) of the threaded RTS?

The reason we added it to the compiler was so that you could use 
programs that require -threaded under GHCi.  Without it, these programs 
cannot be used with GHCi.

In general, -threaded is the way forward, and at some point I hope we 
can make it the default (I was considering this for 6.6, actually). 
Without -threaded, all FFI calls block the other threads in the program, 
and this makes it impossible to do lots of things.

> It doesn't work under solaris and under linux [1] my nightly compilation
> jobs are "killed" every tuesday morning (!) for some reason that i
> cannot reproduce. I suspect the threaded RTS and heavy load. I had no
> such problems with ghc-6.4.1 before.

What version of glibc are you using on Linux?  There were bugs in glibc 
that could cause deadlocks occasionally, I remember having to upgrade 
glibc on our RedHat 9 box a while back.

We know about the threaded RTS bugs on Sparc, and 6.4.3 won't be 
released without a fix for this.  I'm actually quite glad that we've 
forced this into the open with 6.4.2, otherwise the bug would probably 
have remained dormant, affecting only those who used -threaded on Sparc.

Cheers,
	Simon