Date: Sat, 2 Jul 2011 20:33:21 +0200 From: Ulrich =?utf-8?B?U3DDtnJsZWlu?= <uqs@spoerlein.net> To: Doug Barton <dougb@FreeBSD.org> Cc: src-committers@FreeBSD.org, svn-src-all@FreeBSD.org, Robert Watson <rwatson@FreeBSD.org>, Joel Dahl <joel@FreeBSD.org>, svn-src-head@FreeBSD.org, Warner Losh <imp@bsdimp.com> Subject: Re: svn commit: r222980 - in head/sys: amd64/conf i386/conf Message-ID: <20110702183320.GB8485@acme.spoerlein.net> In-Reply-To: <4DF3D633.5060506@FreeBSD.org> References: <201106110908.p5B98kkE066709@svn.freebsd.org> <alpine.BSF.2.00.1106111403060.44950@fledge.watson.org> <4DF3B12C.8020505@FreeBSD.org> <9583277B-6EC0-4B7F-9640-2B128A96C6B8@bsdimp.com> <4DF3D633.5060506@FreeBSD.org>
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On Sat, 11.06.2011 at 13:55:15 -0700, Doug Barton wrote: > On 6/11/2011 1:02 PM, Warner Losh wrote: > > > > On Jun 11, 2011, at 12:17 PM, Doug Barton wrote: > > > >> On 6/11/2011 6:07 AM, Robert Watson wrote: > >>> To me, this seems like the wrong direction. Over the last decade, we've > >>> been trying to move away from conditional compilation of features to > >>> having them be loadable as modules. > >> > >> FWIW, I agree. I'm wondering though, is there still a performance penalty for modules? My understanding in the past was that there is, although for most use cases it's in the statistical noise. Is that still true? > > > > At run time, I believe that's true. At load time, lots of modules can take a few seconds longer. > > I have 3 or 4 modules loaded via loader.conf at boot time. They take at > least 2 seconds each. IMO loading everything via loader.conf would slow > the boot so much as to be a non-starter. > > OTOH, I could imagine an rc.d script that depends on mountcritlocal that > could load a list of modules. Unless I'm missing something that would be > several times faster. I suspect this is your BIOS' fault. I load 22 modules via loader.conf and the loader takes 2, at most 3, seconds to load them all (next to the kernel). This is true for all machines that I own/owned. As you can guess, I'm very much in favour of moving modules from GENERIC to loader.conf ... Uli
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