[Ecls-list] [sage-devel] Re: Build of ECL breaks for parallel builds.

[Dr. David Kirkby]

On 06/18/10 08:56 PM, Juan Jose Garcia-Ripoll wrote:
> On Fri, Jun 18, 2010 at 6:12 PM, Dr. David Kirkby
> <david.kirkby at onetel.net>wrote:
>
>> If one attempts to build ECL 10.4.1 (latest available stable release) in
>> parallel, so the build goes wrong
>
>
> Yes, this is known, but I do not have time / skills to track the
> dependencies that break this. In general I run away from parallel builds for
> my software because they cause headaches, forcing one to really sort the
> dependency graph manually so as not to break anything.

OK, thank you. It would be worth adding something to the Makefile to stop 
parallel builds in that case. I think you can add something like ".NOTPARALLEL", 
though I don't know exactly how to do it.

> Incidentally you complain about ECL's long build time, but parallel build
> will NOT help you. Since in Sage you already use a previously built GMP
> library (or whatever variant) the largest chunk of time is spent in running
> ECL's compiler, a process that CAN NOT be parallelized, due to delicate
> dependencies in bootstrapping code.

OK, fair enough.

> In any case I am surprised to read that ECL's build time is the bottleneck.
> On my laptop it takes just 1+2 minutes to build it and it is a slow OS X
> machine (32 bits). What build flags are you using?
>
> Juanjo

ECL is certainly not the longest item to build, but it is far from the shortest 
either. There are no flags other than --prefix.

It takes 10 minutes on an old 900 MHz Sun Blade 1000. In comparison, many 
packages take under a minute.

  * Flint 1 minute
  * Readline 2 minutes
  * GD 2 minutes.
  * Matplotlib 4 minutes
  * Cython 4 minutes
  * Gap 5 minutes
  * Lapack 6 minutes.
  * ATLAS 8 minutes
  * MPIR 9 minutes
  * ECL 10 minutes
  * MPFR 10 minutes
  * NTL 12 minutes
  * Python 28 minutes.
  * Singular 40 minutes.

On my Sun Ultra 27 (3.33 GHz Xeon) ECL takes 1 minute and 25 seconds to build, 
so it is not as painful there!

Dave