[Engine-devel] Maven 3 here we come!

[Eyal Edri]

----- Original Message -----
> From: "Yaniv Kaul" <ykaul at redhat.com>
> To: "Doron Fediuck" <dfediuck at redhat.com>
> Cc: engine-devel at ovirt.org, "<arch at ovirt.org>" <arch at ovirt.org>
> Sent: Wednesday, May 23, 2012 11:04:12 PM
> Subject: Re: [Engine-devel] Maven 3 here we come!
> 
> On 05/23/2012 12:59 PM, Doron Fediuck wrote:
> > Hi all,
> > As discussed last month[1], we had to deal with some issues which
> > turned out to be a Maven bug.
> > Thanks to Juan and Asaf's work, our current sources now build
> > properly using Maven 3.
> > So you're all invited to migrate into Maven 3. Other than upgrading
> > your local maven package
> > no other action is needed.
> >
> > For now, Maven 2 will also work for you, but I expect in the future
> > we'd like to make use
> > of some advanced features, so migration to 3 is recommended.
> >
> > Talking about advanced features, an interesting challenge is
> > feedback on parallel builds [2].
> 
> I'm not happy with parallel builds - it creates more java processes,
> each taking quite a bit of memory. This, in turn, causes them to
> swap,
> making everything crawl.
> Took me 22 minutes to compile the webadmin and additional 21 minutes
> for
> the user portal, with -T 4. I've had 3.5GB of swap used (and 7GB
> resident memory with 'java' processes running around).
> It usually takes me
> 
> The command line I've used was:
> mvn -T 4 clean install -Pgwt-admin,gwt-user -DskipTests=true
> -Dmaven.test.skip=true
> 

Have you tried using the mvn -T 1C option (to run one thread per core?)
On some builds it reduced my compilation time in a few min,
but it wasn't consistent.

also, maven says that some of the modules are not thread-safe 
and he will run then sequentially, so perhaps if the modules were re-factored
to fit parallel builds, only then we'll see real improvement. 

> 
> As opposed to 7+ 3 minutes without '-T 4'.
> 
> Y.
> 
> > So whoever wants to try it out and report if it improves run time
> > without breaking anything,
> > will be appreciated.
> >
> > Happy migration!
> >
> > [1]http://lists.ovirt.org/pipermail/arch/2012-April/000490.html
> > [2]https://cwiki.apache.org/MAVEN/parallel-builds-in-maven-3.html
> 
> 
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