Hi, [full cite left for d-ds usage]
* Stephane Chauveau ([EMAIL PROTECTED]) [050825 01:16]: > I was profiling the memory usage of libgtk when discovered something > very strange. > > > As you may know, shared memory are usually mapped in 2 different memory > segments. > The first segment containing constant data & code and is shared by all > applications using the library. > The second segment contains non-constant data and each application gets > its own copy. > > What I discovered is that in the official Debian package for libgtk, a > large part of the constant data is moved from the shared segment to the > non-shared one. > > That is easy to see in the section table dumped with 'objdump' where > the section .rodata is shared while the section .data is not. > > $ objdump -h -w libgtk-x11-2.0.so > > The section size is in the 3rd column > > DEBIAN PACKAGE FROM REPOSITORY: > 11 .rodata 000840cb 000000000021a180 000000000021a180 ... > 21 .data 000233c0 00000000003f1d60 00000000003f1d60 ... > > MY OWN RECOMPILED DEBIAN PACKAGE: > 11 .rodata 000a43ad 00000000001f3180 00000000001f3180 ... > 21 .data 00000748 00000000003f3460 00000000003f3460 ... > > That's 0x0233c0-0x748 = 140KB moved from shared to non-shared > > 140KB of non shared memory per GTK application is HUGE!!! > > The problem does not seem to be limited to libgtk. > I picked a library randomly: libasound > Here are the results: > > DEBIAN PACKAGE FROM REPOSITORY: > > 12 .rodata 00008a78 000000000009f240 000000000009f240 ... > 14 .data 00010e20 00000000001ad000 00000000001ad000 ... > > MY OWN RECOMPILED DEBIAN PACKAGE: > > 12 .rodata 000140f8 000000000009eda0 000000000009eda0 ... > 21 .data 00005740 00000000001cbd20 00000000001cbd20 ... > > For libasound 'only' 0x10e20-0x5740 = 47KB are not shared. > > My first though was that the official debian package was probably > compiled with a different version of gcc. > However, I could not reproduce the official package size with gcc-3.3, > gcc-3.4 and gcc-4.0 so the problem > is probably elsewhere: libtool? binutils ? > > The problem is also not specified to AMD64. The x86 version of libgtk > also has more non-shared data than it should. > > I would like to file a bug I do not in which package. Thanks for this valuable hint. However, debian-devel is the better auditorium, so I added them to the Cc-list. Perhaps one of the people there can throw some light at this issue. Cheers, Andi -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
