Re: Bug#384565: [Monotone-devel] Re: Bug#384565: monotone - FTBFS: Build killed with signal 15

[Nathaniel Smith]

On Tue, Nov 21, 2006 at 02:04:07PM -0700, Shaun Jackman wrote:
> It appears the BOOST_SP_DISABLE_THREADS is the source of monotone's
> cross-platform issues on Debian. Namely, that monotone fails to run
> (deadlock) on s390, hppa, sparc, mips, and mipsel, but runs fine on
> i386, amd64, ia64, alpha and powerpc [1].
> 
> [1] http://buildd.debian.org/build.php?pkg=monotone
> 
> One suggested workaround (by Roman Zippel above) is to remove
> -DBOOST_SP_DISABLE_THREADS. The ChangeLog indicates that Nathaniel
> added this feature on 2005-09-30.

Right, makes sense.  Thanks, Roman, for tracking this down.

> So, my questions for the monotone mailing list are...
> 
> 1. Is this more likely a bug in Boost or a bug in monotone?

It is sort of an unfortunate fact of life.  But monotone is the
simplest place to work around it.

> 2. Is it reasonable to workaround this bug by removing
> -DBOOST_SP_DISABLE_THREADS?

Yes, that should work fine, with only some slowdown.

> 3. Is it worth going to the extra effort to only define
> -DBOOST_SP_DISABLE_THREADS on the platforms for which it works? I'll
> consider this last option if it means a performance improvement of at
> least, say arbitrarily, a factor of two or so.
> 
> Debian's freeze and release of Etch is imminent, and I'd like to nail
> this bug before then. Otherwise, Etch will ship with the last bug-free
> version of monotone, which was 0.28.

I have not had a chance to run any benchmarks.  It's certainly less
than a factor of 2.  Shipping with 0.28 would not be the end of the
world (at least it's post-0.26, unlike IIRC latest ubuntu!), but I
would say go ahead and do it.

(If anyone wants to run some benchmarks of how monotone's speed
changes on some interesting operations with and without
-DBOOST_SP_DISABLE_THREADS, that would be cool; we added it as
something that would give _some_ win with no downside, so we've never
actually bothered to check whether the win is even measurable.)

-- Nathaniel

-- 
So let us espouse a less contested notion of truth and falsehood, even
if it is philosophically debatable (if we listen to philosophers, we
must debate everything, and there would be no end to the discussion).
  -- Serendipities, Umberto Eco