Date: Thu, 1 Dec 2005 16:26:38 -0500 From: Kris Kennaway <kris@obsecurity.org> To: Jose Borquez <bsdlists@sbcglobal.net> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: make buildworld run twice as fast Message-ID: <20051201212638.GB6690@xor.obsecurity.org> In-Reply-To: <438F68ED.7000709@sbcglobal.net> References: <438F68ED.7000709@sbcglobal.net>
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[-- Attachment #1 --] On Thu, Dec 01, 2005 at 01:19:41PM -0800, Jose Borquez wrote: > I recently rebuilt my FreeBSD system from sources and it took around 2 > hours on an old PIII 800MHz pc to run "make buildworld". If I include > the -j option to run multiple processes as once such as "make -j2 > buildworld" does that mean it would finish in half the time? No, that would only be true if you were using less than 50% of your resources (e.g. CPU) - for example, if your system has 2 CPUs. Otherwise, on a single CPU machine you are already using close to 100% of CPU, but you may still achieve a few percent speed-up since e.g. one compiler process can be running while another process is blocked waiting for disk I/O. However, this is balanced against increased kernel overhead and memory use. Kris [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD8DBQFDj2qNWry0BWjoQKURAnPzAKCG0Njt9aQD04Umw2BISZXL5BqfAwCfcDuF g5HlQoBiQnp4hQNubh+Q7Wk= =B59r -----END PGP SIGNATURE-----help
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