Date: Fri, 23 Dec 2011 20:10:49 +0000 From: Alexander Best <arundel@freebsd.org> To: Dimitry Andric <dim@FreeBSD.org> Cc: Kostik Belousov <kostikbel@gmail.com>, Garrett Cooper <yanegomi@gmail.com>, freebsd-current@freebsd.org, Benjamin Kaduk <kaduk@mit.edu> Subject: Re: [patch] Cleaning up amd64 kernel optimization options Message-ID: <20111223201049.GA854@freebsd.org> In-Reply-To: <4EF4D0C0.7080808@FreeBSD.org> References: <4EF34E52.2040905@FreeBSD.org> <20111223005932.GA65042@freebsd.org> <25FBBF23-CDFA-429E-966D-A90409D8F2BD@gmail.com> <201112230937.08971.jhb@freebsd.org> <20111223160032.GA18839@freebsd.org> <4EF4B46E.7000405@FreeBSD.org> <20111223175504.GK50300@deviant.kiev.zoral.com.ua> <4EF4D0C0.7080808@FreeBSD.org>
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On Fri Dec 23 11, Dimitry Andric wrote: > On 2011-12-23 18:55, Kostik Belousov wrote: > >On Fri, Dec 23, 2011 at 06:03:42PM +0100, Dimitry Andric wrote: > ... > >>The only thing my patch makes sure of, is that amd64 does the same thing > >>as all other arches, e.g.: compile with a low optimization settings for > >>debug (-O, which is equivalent to -O1), compile with arch-specific high > >>optimization settings for release (-O2 plus whatever is required for the > >>arch, or lower if optimization breaks things). > > > >Release is built with -g for long time, this is where the symbol files > >in /boot/kernel comes from. > > Ah, that is done via 'makeoptions DEBUG=-g' in the kernel configuration > file, right? I didn't realize that was kept in for a release. But even > in that case, amd64 is somehow different from the other arches, which > all get compiled with -O instead. > > If people prefer that to stay as it is, I'll change the diff so only > -frename-registers gets removed when clang is used, as clang does not > support this flag. i think you should go ahead with the changes: 1) get amd64 in line with the other archs when debugging was requested (turning the default optimisation from -O2 to -O) 2) only specify -frename-registers on amd64, when gcc is the requested compiler i'd say: commit it. :) ...sorry we got carried away, but optimisation flags tend to trigger a lot of discussion. ;) cheers. alex
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