how can i tell rpmbuild to *not* parallelize make during the build?

[Robert P. J. Day]

On Tue, 11 Feb 2014, Panu Matilainen wrote:

> On 02/10/2014 10:41 PM, Robert P. J. Day wrote:
> > On Mon, 10 Feb 2014, Rick Stevens wrote:
> >
> > > On 02/10/2014 12:09 PM, Robert P. J. Day issued this missive:
> > > >
> > > >     grrrrrr ... following the instructions here:
> > > >
> > > > https://fedoraproject.org/wiki/Building_a_custom_kernel
> > > >
> > > > on how to build a custom kernel (some of which is incorrect, more on
> > > > that later), and builds keep failing at random places, i'm guessing
> > > > because i have a hyperthreaded quad-core laptop, and the "make -j8" is
> > > > simply tripping over itself in arbitrary places.
> > > >
> > > >     what's the easiest way to specify a single-threaded build? yes, it
> > > > will take forever, but it will be nice to verify that that's the
> > > > problem.
> > > >
> > > >     thanks.
> > > >
> > > > rday
> > >
> > > Theoretically you could do
> > >
> > >  MAKEFLAGS="-j 1" rpmbuild blah-blah
> > >
> > > gmake looks for the environment variable "MAKEFLAGS". Most reasonable
> > > makefiles do "MAKEFLAGS+=other-specific-flags", so it should honor it.
> > > Keep in mind that if there are multiple "-j" variables to gmake, it will
> > > only honor the LAST one specified. YMMV.
> >
> >    well, this is interesting ... i found the variable "smp_mflags" in
> > kernel.spec, so i ran:
> >
> >    $ rpmbuild --showrc
> >
> > to see how it was being set, and found the following:
> >
> > -14: _smp_mflags        %(
> >      [ -z "$RPM_BUILD_NCPUS" ] \
> >          && RPM_BUILD_NCPUS="`/usr/bin/nproc 2>/dev/null || \
> >                               /usr/bin/getconf _NPROCESSORS_ONLN`"; \
> >      if [ "$RPM_BUILD_NCPUS" -gt 16 ]; then \
> >          echo "-j16"; \
> >      elif [ "$RPM_BUILD_NCPUS" -gt 3 ]; then \
> >          echo "-j$RPM_BUILD_NCPUS"; \
> >      else \
> >          echo "-j3"; \
> >      fi )
> >
> > which i find fascinating since, if you follow the logic, even if you
> > use "RPM_BUILD_NCPUS=1", that code above will still set it to 3. :-)
>
> That'd be from your ~/.rpmmacros as set up by rpmdev-setuptree, not
> from rpm itself. The rationale is to detect parallel build problems
> in package makefiles on non-smp systems so the packager knows to
> avoid %{?_smp_mflags} with make in %build.

  argh ... i didn't even realize that "rpmdev-setuptree" created a
personal .rpmmacros file for me; i'm so used to creating that entire
build structure myself manually.

> Note that the kernel build is known to work with parallel build, so
> the problems you're seeing are something else, such as subtly faulty
> components (cpu/memory/motherboard...) that trip up when pushed
> hard, or overheating.

  i'm willing to believe that, although this ASUS quad core has
massive cooling vents on the back, so maybe i'll run memtest on it for
a while and see what shakes out. as it is, just dropping
parallelization down to 3 seems to solve the problem, for what that's
worth.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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