Date: Thu, 27 Jan 2011 19:04:23 -0500 From: Alexander Kabaev <kabaev@gmail.com> To: Joerg Sonnenberger <joerg@britannica.bec.de> Cc: freebsd-hackers@freebsd.org Subject: Re: rtld optimizations Message-ID: <20110127190423.785cb2d3@kan.dnsalias.net> In-Reply-To: <20110127234737.GA31603@britannica.bec.de> References: <201101271305.21510.naylor.b.david@gmail.com> <AANLkTinkhfso3iRR4pERxhf=%2BnCqy2YDigzgyfNVtnaJ@mail.gmail.com> <20110127203126.GN2518@deviant.kiev.zoral.com.ua> <1296161448.20060.40.camel@dt.vicor.com> <20110127205907.GP2518@deviant.kiev.zoral.com.ua> <1296162754.20060.42.camel@dt.vicor.com> <20110127213536.GR2518@deviant.kiev.zoral.com.ua> <1296165538.20060.43.camel@dt.vicor.com> <AANLkTimCVnqN7WAGfP7GtVZreBv%2BpXKFWRWqPDnAADhC@mail.gmail.com> <20110127182418.77c53c60@kan.dnsalias.net> <20110127234737.GA31603@britannica.bec.de>
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--Sig_/rkOlWEZaVxTAWFpFqlO2mmx Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 28 Jan 2011 00:47:37 +0100 Joerg Sonnenberger <joerg@britannica.bec.de> wrote: > On Thu, Jan 27, 2011 at 06:24:18PM -0500, Alexander Kabaev wrote: > > For starters, the number of libraries given binary is linked too is > > completely and utterly irrelevant :) The change NetBSD guys claims > > to revolutionize his application startup times only applies to > > programs that dlopen (read - load dynamically) libraries with long > > largely identical dependency chains and calls dlsym on them many, > > many thousand times. I do not think you will find any real app out > > there that fits this description close enough to actually > > demonstrate the effect of the change that is distinguishable from > > the statistical noise. Pressing ^C certainly not precise enough for > > that. >=20 > (1) The program itself needs to have a large enough number of linked > libraries. That is wrong, of course. symlook_needed is only called when dlsym(<real object handle>, <symbol name>) is called and the number of objects on main and global DAGS is very much an irrelevant detail hereirrelevant here. > (2) The program needs to dlopen() modules. Yep. > (3) The program needs to search for missing symbols often enough. > ... by means of explicit dlsym() call. =20 > From memory, the real world example that fulfilled all three cases was > Evolution. (1) and (2) are pretty typical though. >=20 Never claimed otherwise. It is just ones with nested trees deep enough to matter is what in very short supply. I would be very interested in seeing the Evolution benchmarked, but I dount very much than even Evolution will manage to break through statistical noise. --=20 Alexander Kabaev --Sig_/rkOlWEZaVxTAWFpFqlO2mmx Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (FreeBSD) iD8DBQFNQggMQ6z1jMm+XZYRAoyYAKCeGHhlVjj4thRtrzfL6Pq68zz96wCg2suV /0BQGbO16Ms3/q/kXqq/NL4= =0/Zp -----END PGP SIGNATURE----- --Sig_/rkOlWEZaVxTAWFpFqlO2mmx--
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