Date: Fri, 6 Feb 2004 03:19:46 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Ruslan Ermilov <ru@FreeBSD.org> Cc: current@FreeBSD.org Subject: Re: Very long SRCS list with unusually long src/ prefix Message-ID: <20040206030956.F11456@gamplex.bde.org> In-Reply-To: <20040205151425.GA18523@FreeBSD.org.ua> References: <20040205091634.GC13932@FreeBSD.org.ua> <20040206012805.N8113@gamplex.bde.org> <20040205151425.GA18523@FreeBSD.org.ua>
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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}
> > % + @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}
> : @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.
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").
> > % ${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
Bruce
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