Re: On the cost of libraries
- From: Drazen Kacar <dave arsdigita com>
- To: Owen Taylor <otaylor redhat com>
- Cc: Alex Larsson <alexl redhat com>, Maciej Stachowiak <mjs noisehavoc org>, Drazen Kacar <dave arsdigita com>, gnome-hackers gnome org
- Subject: Re: On the cost of libraries
- Date: Sun, 2 Sep 2001 05:57:06 +0200
Owen Taylor wrote:
> Let's first get some hard data.
What kind of data would you prefer?
> I find it a little hard to believe that exporting a single variable
> causes more than a single variables worth runtime link overhead.
Just the first one, in certain circumstances. Any additional symbol
doesn't incur overhead.
I can offer xemacs as an example.
"ldd xemacs" shows:
libtiff.so.1 => /usr/local/lib/libtiff.so.1
libpng.so.2 => /usr/local/lib/libpng.so.2
libjpeg.so.1 => /usr/local/lib/libjpeg.so.1
libgdk_imlib.so.1 => /usr/local/lib/libgdk_imlib.so.1
libgtk-1.2.so.0 => /usr/local/lib/libgtk-1.2.so.0
libgdk-1.2.so.0 => /usr/local/lib/libgdk-1.2.so.0
libX11.so.4 => /usr/lib/libX11.so.4
libglib-1.2.so.0 => /usr/local/lib/libglib-1.2.so.0
libdl.so.1 => /usr/lib/libdl.so.1
libdb-3.2.so => /usr/local/lib/libdb-3.2.so
libgdbm.so.1 => /usr/local/lib/libgdbm.so.1
libcurses.so.1 => /usr/lib/libcurses.so.1
libldap.so.4 => /usr/lib/libldap.so.4
libm.so.1 => /usr/lib/libm.so.1
libsocket.so.1 => /usr/lib/libsocket.so.1
libnsl.so.1 => /usr/lib/libnsl.so.1
libgen.so.1 => /usr/lib/libgen.so.1
libc.so.1 => /usr/lib/libc.so.1
libz.so.1 => /usr/lib/libz.so.1
libXext.so.0 => /usr/lib/libXext.so.0
libgif.so.3 => /usr/local/lib/libgif.so.3
libgmodule-1.2.so.0 => /usr/local/lib/libgmodule-1.2.so.0
libgnuintl.so.1 => /usr/local/lib/libgnuintl.so.1
libresolv.so.2 => /usr/lib/libresolv.so.2
libmp.so.2 => /usr/lib/libmp.so.2
libdga.so.1 => /usr/openwin/lib/libdga.so.1
/usr/platform/SUNW,Ultra-250/lib/libc_psr.so.1
Then, on "xemacs -nw" process, mapping is as follows:
18260: ./xemacs -nw
Address Kbytes Resident Shared Private Permissions Mapped File
00010000 1784 1784 1568 216 read/exec xemacs
001DC000 3488 3488 1408 2080 read/write/exec xemacs
00544000 288 288 - 288 read/write/exec [ heap ]
FEC70000 168 112 40 72 read/exec libcurses.so.1
FECAA000 32 32 - 32 read/write/exec libcurses.so.1
FECB2000 8 8 - 8 read/write/exec libcurses.so.1
FECC0000 24 24 16 8 read/exec nss_files.so.1
FECD6000 8 8 - 8 read/write/exec nss_files.so.1
FECE0000 16 16 8 8 read/exec libmp.so.2
FECF4000 8 8 - 8 read/write/exec libmp.so.2
FED00000 552 432 352 80 read/exec libnsl.so.1
FED9A000 32 32 - 32 read/write/exec libnsl.so.1
FEDA2000 32 24 - 24 read/write/exec libnsl.so.1
FEDD0000 72 32 - 32 read/exec libdga.so.1
FEDF2000 8 8 - 8 read/write/exec libdga.so.1
FEE00000 40 32 24 8 read/exec libsocket.so.1
FEE1A000 8 8 - 8 read/write/exec libsocket.so.1
FEE20000 96 16 8 8 read/exec libXext.so.0
FEE48000 8 8 - 8 read/write/exec libXext.so.0
FEE50000 88 88 80 8 read/exec libm.so.1
FEE74000 8 8 - 8 read/write/exec libm.so.1
FEE80000 560 224 64 160 read/exec libX11.so.4
FEF1C000 24 24 - 24 read/write/exec libX11.so.4
FEF30000 24 16 - 16 read/exec libgnuintl.so.1
FEF44000 16 16 - 16 read/write/exec libgnuintl.so.1
FEF50000 184 120 - 120 read/exec libglib-1.2.so.0
FEF8C000 32 24 - 24 read/write/exec libglib-1.2.so.0
FEFA0000 248 96 - 96 read/exec libgdk-1.2.so.0
FEFEC000 32 32 - 32 read/write/exec libgdk-1.2.so.0
FF000000 1976 712 - 712 read/exec libgtk-1.2.so.0
FF1FC000 296 136 - 136 read/write/exec libgtk-1.2.so.0
FF250000 8 8 - 8 read/write/exec [ anon ]
FF260000 8 8 - 8 read/exec libgmodule-1.2.so.0
FF270000 8 8 - 8 read/write/exec libgmodule-1.2.so.0
FF280000 672 608 592 16 read/exec libc.so.1
FF338000 24 24 - 24 read/write/exec libc.so.1
FF33E000 8 8 - 8 read/write/exec libc.so.1
FF350000 8 8 - 8 read/write/exec [ anon ]
FF360000 16 16 8 8 read/exec libc_psr.so.1
FF380000 8 8 - 8 read/exec libdl.so.1
FF390000 8 8 8 - read/shared dev:32,4 ino:202286
FF3A0000 8 8 - 8 read/write/exec [ anon ]
FF3B0000 136 136 128 8 read/exec ld.so.1
FF3E2000 8 8 - 8 read/write/exec ld.so.1
FFBE4000 48 48 - 48 read/write/exec [ stack ]
You will notice a certain number of libraries missing, because they just
weren't used yet. There's GTK and all its dependencies because I didn't
use lazy loading when linking libgtk, so all the libraries it depends on
were pulled in.
ldd /usr/local/lib/libgtk.so
libgdk-1.2.so.0 => /usr/local/lib/libgdk-1.2.so.0
libgmodule-1.2.so.0 => /usr/local/lib/libgmodule-1.2.so.0
libglib-1.2.so.0 => /usr/local/lib/libglib-1.2.so.0
libX11.so.4 => /usr/lib/libX11.so.4
libm.so.1 => /usr/lib/libm.so.1
libgnuintl.so.1 => /usr/local/lib/libgnuintl.so.1
libc.so.1 => /usr/lib/libc.so.1
libXext.so.0 => /usr/lib/libXext.so.0
libdl.so.1 => /usr/lib/libdl.so.1
libsocket.so.1 => /usr/lib/libsocket.so.1
libnsl.so.1 => /usr/lib/libnsl.so.1
libdga.so.1 => /usr/openwin/lib/libdga.so.1
libmp.so.2 => /usr/lib/libmp.so.2
/usr/platform/SUNW,Ultra-250/lib/libc_psr.so.1
Hmm, I suppose the next time I'll use lazy loading for GTK as well. Even
if it has to be loaded, libX11 and libXext (and hopefully some others) don't.
Although this could probably go into bug report.
Anyway, all those Guppi libraries are perfectly fine for this OS, as long
as they don't cause copy relocations. They just wouldn't be loaded until
needed.
--
.-. .-. Errors have been made. Others will be blamed.
(_ \ / _)
|
| dave arsdigita com
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