Re: Very long SRCS list with unusually long src/ prefix

On Fri, Feb 06, 2004 at 03:19:46AM +1100, Bruce Evans wrote:
> On Thu, 5 Feb 2004, Ruslan Ermilov wrote:
> 
> > On Fri, Feb 06, 2004 at 01:40:45AM +1100, Bruce Evans wrote:
> > > On Thu, 5 Feb 2004, Ruslan Ermilov wrote:
> > [...]
> > > % +.for f in ${DPSRCS:M*.[cS]} ${DPSRCS:M*.cc} ${DPSRCS:M*.C} ${DPSRCS:M*.cpp} \
> > > % +    ${DPSRCS:M*.cxx} ${DPSRCS:M*.m}
> > > % +_mkdep_${f}: ${f}
> > > % +	_at_echo ${.ALLSRC}
> > > % +.endfor
> > >
> > > This seems to run echo once for each file separately.  It should be deemed
> > > inefficient :-).
> > >
> > But that's what this patch basically does: it splits possibly very
> > long ${.ALLSRC} list into pieces.  It's very inefficient only in
> > traditional mode.  Run this with and without -j1 to see the diff:
> >
> > : COUNT!=	jot 1000
> > :
> > : all:
> > : .for foo in ${COUNT}
> > : 	_at_echo $$$$ >/dev/null
> > : .endfor
> 
> That is slow too.  I get 12.12 seconds with make, 2.36 with make -j1,
> 1.37 with a shell loop and bash-1, 1.35 with a shell loop and /bin/sh,
> and 0.0042 with jot 1000 >/dev/null.
> 
Shell loops aren't an option here.  I realize that we loose speed here,
but we gain a feature.

> I wonder about all those little dependencies too.  make already takes
> a noticeable amount of time to handle large subdirs (here it takes 0.48
> seconds for a null "make depend").
> 
I see the 0.18 secs increase for "make depend" in bin/cat.  I see no
increase when .depend is not stale (since this code is not run then).
What do you mean by a ``null "make depend"''?

> > > %  ${DEPENDFILE}: ${DPSRCS}
> > > %  	rm -f ${DEPENDFILE}
> > > %  .if !empty(DPSRCS:M*.[cS])
> > > % -	${MKDEPCMD} -f ${DEPENDFILE} -a ${MKDEP} \
> > > % -	    ${CFLAGS:M-nostdinc*} ${CFLAGS:M-[BID]*} \
> > > % -	    ${.ALLSRC:M*.[cS]}
> > > % +	(cd ${.CURDIR}; ${MAKE} _mkdep_cS) | xargs env \
> > > % +	    ${MKDEPCMD} -f ${DEPENDFILE} -a ${MKDEP} \
> > > % +	    ${CFLAGS:M-nostdinc*} ${CFLAGS:M-[BID]*}
> > >
> > > make uses a real shell, so the env shouldn't be needed.
> > >
> > $ echo foo.c | xargs CC=cc mkdep
> > xargs: CC=cc: No such file or directory
> 
> $ echo foo.c | CC=cc xargs mkdep
> 
Yes, but ``grep ^MKDEPCMD bsd.dep.mk'' to see what I'm talking
about.


Cheers,
-- 
Ruslan Ermilov
FreeBSD committer
ru_at_FreeBSD.org