Re: [CFT] build: WITH_FAST_DEPEND and WITH_CCACHE_BUILD

On Thu, 12 Nov 2015 21:04:53 -0800
Craig Rodrigues <rodrigc_at_FreeBSD.org> wrote: 

> On Thu, Nov 12, 2015 at 9:40 AM, Bryan Drewery <bdrewery_at_freebsd.org> wrote:
> 
> > - The first is WITH_FAST_DEPEND. Please see the commit for its full
> >  
> 
> I have enabled WITH_FAST_DEPEND in make.conf for several builds.

I have enabled it in src.conf ( head_at_r290570, GENERIC-NODEBUG kernel)

On hw.model: Intel(R) Xeon(R) CPU           E5504  _at_ 2.00GHz 
time make -j8 buildworld:

3685.33 real     25176.56 user      1918.05 sys WITH_FAST_DEPEND
3904.77 real     25833.18 user      2327.22 sys  without

> (1)     Job: https://jenkins.freebsd.org/job/FreeBSD_HEAD
>          Before WITH_FAST_DEPEND:
> https://jenkins.freebsd.org/job/FreeBSD_HEAD/3488/    1 hour, 23 minutes
>          After WITH_FAST_DEPEND:
> https://jenkins.freebsd.org/job/FreeBSD_HEAD/3497/ ,      1 hour, 17 minutes
> 
>          Compiler used: clang
> 
> (2)   Job: https://jenkins.freebsd.org/job/FreeBSD_HEAD_sparc64/
>         Before WITH_FAST_DEPEND:
> https://jenkins.freebsd.org/job/FreeBSD_HEAD_sparc64/1309/ , 23 minutes
>         After WITH_FAST_DEPEND:
> https://jenkins.freebsd.org/job/FreeBSD_HEAD_sparc64/1329/ , 22 minutes
> 
>         Compiler used: gcc 4.2.1
> 
> (3)  Job: https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc4.9/
>        Before WITH_FAST_DEPEND:
> https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc4.9/761/ , 1 hour, 7
> minutes
>        After WITH_FAST_DEPEND:
> https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc4.9/762/ , 1 hour 2
> minutes
> 
>        Compiler:  gcc 4.9.2
> 
> The timings are not very scientific, because the VM's in which the builds
> are occurring are
> very loaded, since each build host is running multiple VM's, which are
> building different things.
> 
> This gives you a basic idea though, that WITH_FAST_DEPEND works on a few
> compilers (clang, gcc 4.2, gcc 4.9),
> and there is some build time reduction, and no increase in build time.
> 
> Congratulations for tackling this stuff in FreeBSD.  As you mentioned, this
> area has not been touched
> in 14 years.
> --
> Craig

--
wbr, tiger