Date: Thu, 10 May 2001 17:45:47 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Warner Losh <imp@harmony.village.org> Cc: Mikhail Teterin <mi@misha.privatelabs.com>, eric@FreeBSD.org, mi@aldan.algebra.com, knu@iDaemons.org, will@physics.purdue.edu, sobomax@FreeBSD.org, kris@obsecurity.org, kris@FreeBSD.org, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: port policies Message-ID: <Pine.BSF.4.21.0105101736530.917-100000@besplex.bde.org> In-Reply-To: <200105091729.f49HTab38677@harmony.village.org>
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On Wed, 9 May 2001, Warner Losh wrote: > In message <Pine.BSF.4.21.0105091924090.17145-100000@besplex.bde.org> Bruce Evans writes: > : -j2 on a single-CPU machine with 2 disks (src on one, obj and root on the > : other) was a little slower and consumed more resources for makeworld > : the last time I checked. It might be faster because the disk(s) are too > : slow relative to the CPU and/or the VMIO cache is too small. It's hard > : to see how it could consume less resources. > > I think that people are getting confused because for a kernel build -j > 2 or -j 3 can be up to 10-15% faster than no -j flags at all. They > figure this translates well to the rest of the system. I did a quick but not very well controlled test involving "make cleandir; make obj; make depend; time make" in perl, but the result was so unfavourable for -j2 that I didn't believe it. The perl build is less gcc-bound than most of buildworld, so I would have expected it to favour -j2 more than buildworld but not be very different from makeworld. I also wouldn't expect -j2 to speed up building kernels (at least without modules) on uniprocessors. Here the build is 98% cpu-bound after the first run (all the source files fit in the disk cache). Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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