Date: Mon, 28 Jun 2004 13:11:04 +0000 From: Dave Hart <davehart@gmail.com> To: Chris Stenton <jacs@gnome.co.uk> Cc: freebsd-smp@freebsd.org Subject: Re: setiathome issues on 5.2.1 SMP Message-ID: <85d95418040628061151d9e0e@mail.gmail.com> In-Reply-To: <004101c45921$4f6e0660$4b7ba8c0@gnome.co.uk> References: <004101c45921$4f6e0660$4b7ba8c0@gnome.co.uk>
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On Wed, 23 Jun 2004 13:55:07 +0100, Chris Stenton <jacs@gnome.co.uk> wrote: > > I have 2 xeon processors and thus when I start setiathome I get 4 copies > started. > > When I do make -j8 buildworld I notice a 20% performance improvement when > I remove setiathome. I am sure when I tried this a couple of years ago on my > old P4 that the difference was not so marked on a single processor. [...] Were you testing with two logical processors on that single P4 (hyperthreading)? It seems to me you have two issues, one is SMP, the other SMP on top of virtual processors provided by hyperthreading. To be more comparable with your experience a couple of years ago on your old P4, you should compare make -j4 buildworld alone vs. with setiathome on a system with hyperthreading disabled (logical CPUs halted). Dave Hart
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