Date: Wed, 9 Jan 2013 03:34:00 +1100 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Garrett Cooper <yanegomi@gmail.com> Cc: Barney Cordoba <barney_cordoba@yahoo.com>, Erich Dollansky <erichsfreebsdlist@alogt.com>, freebsd-net@freebsd.org Subject: Re: To SMP or not to SMP Message-ID: <20130109032940.H30575@sola.nimnet.asn.au> In-Reply-To: <D889FFD5-6832-43B9-A6BA-93111C619F35@gmail.com> References: <1357660252.29936.YahooMailClassic@web121603.mail.ne1.yahoo.com> <D889FFD5-6832-43B9-A6BA-93111C619F35@gmail.com>
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On Tue, 8 Jan 2013 07:57:04 -0800, Garrett Cooper wrote: > On Jan 8, 2013, at 7:50 AM, Barney Cordoba wrote: > > > --- On Mon, 1/7/13, Erich Dollansky <erichsfreebsdlist@alogt.com> wrote: > > > >> From: Erich Dollansky <erichsfreebsdlist@alogt.com> > >> Subject: Re: To SMP or not to SMP > >> To: "Barney Cordoba" <barney_cordoba@yahoo.com> > >> Cc: freebsd-net@freebsd.org > >> Date: Monday, January 7, 2013, 10:56 PM > >> Hi, > >> > >> On Mon, 7 Jan 2013 18:25:58 -0800 (PST) > >> Barney Cordoba <barney_cordoba@yahoo.com> > >> wrote: > >> > >>> I have a situation where I have to run 9.1 on an old > >> single core box. > >>> Does anyone have a handle on whether it's better to > >> build a non SMP > >>> kernel or to just use a standard SMP build with just > >> the one core? > >>> Thanks. > >> > >> I ran a single CPU version of FreeBSD until my last single > >> CPU got hit > >> by a lightning last April or May without any problems. > >> > >> I never saw a reason to include the overhead of SMP for this > >> kind of > >> machine and I also never ran into problems with this. > > > > Another "ass"umption based on logic rather than empirical evidence. > > It isn't really an offhanded assumption because there _is_ > additional overhead added into the kernel structures to make things > work SMP with locking :). Whether or not it's measurable for you and > your applications, I have no idea. > HTH, > -Garrett Where's Kris Kennaway when you need something compared, benchmarked under N different types of loads, and nicely graphed? Do we have a contender? :) cheers, Ian
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