depend + all vs dependall
Ruslan Ermilov
ru at freebsd.org
Mon Mar 31 03:24:48 PST 2003
On Mon, Mar 31, 2003 at 09:06:07PM +1000, Bruce Evans wrote:
> On Mon, 31 Mar 2003, Ruslan Ermilov wrote:
>
> > On Mon, Mar 31, 2003 at 05:04:42PM +1000, Bruce Evans wrote:
> > > On Mon, 31 Mar 2003, Ruslan Ermilov wrote:
> > > > ...
> > > > Also, your test is not honest because original Makefile.inc1
> > > > did not parallelize the "all" stage of "buildworld", by not
> > > > implementing par-all. Last time I tried par-all, it saved
> > > > me 16% of time from the -j8 buildworld:
> > > >
> > > > 26m8.74s real 26m13.08s user 11m9.70s sys (old)
> > > > 21m48.52s real 26m20.60s user 11m4.95s sys (new)
> > > >
> > > > Attached is the message with the patch. It has some Russian,
> > > > but also includes a patch. Note that par-all only parallelizes
> > > > top-level bsd.subdir.mk makefiles, as we depend on the ordering
> > > > of traversing SUBDIRs in a few places. The plan is to drop
> > > > this assumption in places that don't need this ordering.
> > >
> > > Please benchmark mainly for the usual case of non-SMP :-).
> > >
> > You mean for the non-SMP case but with -j?
>
> Mainly the non-SMP case without -j. -j is currently too broken to give
> anything except pessimizations for the non-SMP case, and it would not be
> clear if optimizations for it are just side effects of not going near
> the bug. After it is fixed then it will double the number of combinations
> to test.
>
Without -j, my patch obviously has no effect on either [non-]SMP
systems, as "par-all" becomes a plain "all". See also below.
> > On a Celeron 800 system with ATA100 disk using -j4 -DNOCLEAN buildworld
> > of RELENG_4 a friend reported the following times:
> >
> > Without patch With patch
> > real 69m43.271s 69m26.722s
> > user 38m22.009s 38m19.384s
> > sys 10m45.273s 10m41.596s
> >
> > Further reports show that on single-CPU systems with large CPU
> > cache the real time win was near what I have reported for 2-CPU
> > box, and it had no effect on small cache single-CPU systems and
> > -j builds.
>
> I think I understand why it often makes little difference: it saves
> a tree traversal, but costs an extra make process for each leaf
> directory.
>
Hardly so. My patch doesn't affect leaf directories; only
level 1 bsd.subdir.mk makefiles (*bin*/Makefile, etc.) are
affected by this parallelization.
Cheers,
--
Ruslan Ermilov Sysadmin and DBA,
ru at sunbay.com Sunbay Software AG,
ru at FreeBSD.org FreeBSD committer,
+380.652.512.251 Simferopol, Ukraine
http://www.FreeBSD.org The Power To Serve
http://www.oracle.com Enabling The Information Age
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