Date: Sun, 10 Aug 1997 11:43:37 -0600 From: Steve Passe <smp@csn.net> To: nnd@itfs.nsk.su Cc: current@FreeBSD.ORG Subject: Re: Make and SMP - what can be done ? Message-ID: <199708101743.LAA11578@Ilsa.StevesCafe.com> In-Reply-To: Your message of "10 Aug 1997 11:30:41 GMT." <5sk8p1$ld3@news.itfs.nsk.su>
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Hi, > Now when we can use SMP-FreeBSD and there is > a possibility to speedup building various components of > the system (making the kernel with 'make -j12' proves this > very definitely) there is a question - HOW can we use it ? You've touched on a topic dear to my heart! I took a stab at this once and gave up for lack of knowledge of the .mk system and its subltlies. There is a BIG win to be had here, my experiments suggest "make world" could be cut by around 25% if the -j option were added properly, maybe more. --- > More stepwise process may consists in adding global > make flag (say, JFLAG which is set to "-j12" for SMP case > and to "" for traditional systems) and using it in various > parts of word-building alongside with modifying appropriate > Makefiles. I added JMAKEFLAGS= -j12 to /etc/make.conf, then added JMAKEFLAGS to some of the lower level Makefiles, like the ones for libraries. This worked nicely. I found other Makefiles that just needed a little more work on the dependancies, they sometimes need to be more explicit in a parallel world. Things with YACC & LEX passes die horribly. for non SMP kernels the -j option still is a big win. It filters out the time spent spinning while waiting for disk IO, try -j4 when building a kernel on a UP system. --- > Is there any sense in my speculations ? > Does anybody have some propositions for solving this problem ? > And is there REAL problem at all ;-) ? Bottom line is that this is something that REALLY needs doing. You seem to have a good handle on the concept, go for it!!! -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD
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