Date: Sun, 29 Apr 2012 14:22:41 -0400 From: Alexander Kabaev <kabaev@gmail.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: kan@freebsd.org, John Marino <draco@marino.st>, Pedro Giffuni <pfg@freebsd.org>, freebsd-toolchain@freebsd.org Subject: Re: DragonFly added DT_GNU_HASH support to rtld Message-ID: <20120429142241.646db441@kan.dyndns.org> In-Reply-To: <20120415144322.GU2358@deviant.kiev.zoral.com.ua> References: <4F3C5A3A.6050107@FreeBSD.org> <20120216154730.GL3283@deviant.kiev.zoral.com.ua> <4F5C7764.2@marino.st> <20120415144322.GU2358@deviant.kiev.zoral.com.ua>
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--Sig_/g5OYvipX5G=6G26.XpE_.pV Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sun, 15 Apr 2012 17:43:22 +0300 Konstantin Belousov <kostikbel@gmail.com> wrote: > On Sun, Mar 11, 2012 at 10:59:00AM +0100, John Marino wrote: > > Hi Konstantin, > >=20 > > It seems that no BSD supported DT_GNU_HASH despite this option > > being available on the base binutils (FreeBSD's 2.17.50 binutils > > supports it). This gnu extension is a big performance improvement > > over the specified SysV hash. > >=20 > > The guy porting libreoffice to pkgsrc was finding > > -Wl,--hash-style=3Dgnu to be the default build for that package. > > Indeed, using the standard hash results in very long startup times > > for something like Writer (> 8 seconds launched from a SSD) > >=20 > > The result is that we brought in DT_GNU_HASH support to our > > real-time linker this weekend. We're still waiting to see how that > > improves libreoffice startup times. > >=20 > > full commit: > > >http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/7629c6317998f8= 50ebca23c296822ba08af09e5b > >=20 > >=20 > > Modification to base compiler so all system libs and binaries can > > take advantage of it: > > >http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/4687ecd9561d76= f3d02ccb4f7adeecd5e3afdd8f > >=20 > >=20 > > For a while, binaries with dynamic symbol tables will have both > > types of hashes embedded. At some point in the future, we may > > switch over to only generating the GNU hash. This will break > > forward compatibility, but that happens rather frequently for other > > reasons anyway. > >=20 > > I was a bit surprised FreeBSD didn't already have this > > functionality given the performance benefits, so hopefully these > > DragonFly commits will be interesting for you. > >=20 >=20 > I finally ported the Dragonfly commit to FreeBSD. There were several > changes reverted in dragonfly version of the extracted > matched_symbol() function which were restored. I also blindly > converted all non-x86 arches. >=20 > The matched_symbol() extraction is the good opportunity to apply the > style(9) formatting to the large chunk of rtld code. >=20 > Any testers, esp. on non-x86 architectures, are welcome. You would > need to modify gcc spec file for you architecture, see corresponding > x86 changes in contrib/gcc/config/i386. >=20 > For me, patch successfully worked on the machine were I disabled sysv > hashes at all. >=20 > http://people.freebsd.org/~kib/misc/rtld-gnu_hash.1.patch Nothing jumps out, looks good. I am not a fan of mixing and matching different styles within the same file though.=20 --=20 Alexander Kabaev --Sig_/g5OYvipX5G=6G26.XpE_.pV Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iD8DBQFPnYb2Q6z1jMm+XZYRAvzaAJ9wPWBG7egHmFqwDyLwFH125zri1QCeM0es E3xRgyGgvWiCc1hTgo4MW7w= =PU+1 -----END PGP SIGNATURE----- --Sig_/g5OYvipX5G=6G26.XpE_.pV--
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