Proposal: dlopening the file dialog
Thiago Macieira
thiago at kde.org
Thu Mar 29 19:50:11 BST 2007
David Faure wrote:
>- making kio smaller, without all those mostly-internal classes with
> lots of virtual methods, which according to Dirk leads to many
> unnecessary reallocations during startup
Uh, relocations :-)
Yep, that's actually a big cost. One that can be lessened by the use
of -Bsymbolic-functions in KDE code as well as Qt code. Unfortunately,
there's no released version of GNU binutils (ld) that contains that
feature yet. I'd like KDE to support that switch just like Qt does.
It really improves the relocation performance, since it changes the global
relocation (which is string-based and, therefore, requires hash tables
and costly string comparisons on the rather long C++ mangled names) into
local relocations: those are simple pointer arithmetic with the library's
load address. What's more, direct calls will be made with direct relative
jumps, instead of indirect through the PLT.
I don't have the numbers anymore, but when I tested a similar feature in
KDE, it reduced the relocation table size greatly. The number of global
relocations to local symbols dropped from ~1700 to 0 in kdecore.
You can call this the next big step after -fvisibility=hidden.
(The feature that I actually tested was visibility=protected, but that's
currently broken in architectures without PIC executables)
--
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
PGP/GPG: 0x6EF45358; fingerprint:
E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358
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