Date: Mon, 12 Feb 2001 22:47:47 -0800 From: Kent Stewart <kstewart@urx.com> To: Jordan Hubbard <jkh@winston.osd.bsdi.com> Cc: Danny Braniss <danny@cs.huji.ac.il>, freebsd-hackers@FreeBSD.ORG Subject: Re: soft updates performance Message-ID: <3A88D893.ED6442EA@urx.com> References: <81045.982046200@winston.osd.bsdi.com>
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Jordan Hubbard wrote: > > > One other point that I would like to understand is why -j4 takes > > longer on all of my systems. That goes against what everyone claims > > should happen. > > With how many running processors? If you're running -j4 on a > uniprocessor system, you're only introducing competition for already > scarce CPU resources, though -j2 can be a speedup since this allows > one target build to run while another is in an I/O wait. I've only > seen a speedup with -j4 when using at least 2 CPUs. It was a uniprocessor system. The folklore has it doing more but all I ever saw it produce was more competition, which resulted in a longer running buildworld. Kent -- Kent Stewart Richland, WA mailto:kbstew99@hotmail.com http://kstewart.urx.com/kstewart/index.html FreeBSD News http://daily.daemonnews.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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