-z combreloc

[Jack Howarth]

Andrew,
    I'm not sure I understand what you mean. I didn't
mean to imply that change should go into the cvs.
I mean to alert everyone that Debian was taking the
leap in sid to using -z combreloc.
    A few other questions for anyone who would care
to answer...

So far I have been able to test a simple case with prelink
(it always has passed its own make check). I rebuilt zip
with the new binutils 2.11.92.0.5 and found that I got...

howarth@bogus:~/debian6/zip-2.30$ LD_DEBUG=statistics ./zip 
08344:                   number of relocations: 256
08344:        number of relocations from cache: 99

...after prelinking this binary I got...

howarth@bogus:~/debian6/zip-2.30$ LD_DEBUG=statistics ./zip
08355:                   number of relocations: 0
08355:        number of relocations from cache: 16

...and it seems to be running okay. I also tried doing the
same with bash but it complained...

prelink ./bash
prelink: /lib/libncurses.so.5.2: Not enough room to add .dynamic entry

I take this to imply that as far as prelinking goes that
not only does the program in question have to be rebuilt
under a newer binutils but all libs linked in have to
be as well. Is this true?
    Lastly back to -z combreloc...is there a good way to
benchmark any speed up gained by recompiling with that 
option enabled in binutils? Jakub seems to have different
output from LD_DEBUG=statistics than we do (he can get
....

LD_DEBUG=statistics kmail
14751:
14751:  runtime linker statistics:
14751:    total startup time in dynamic loader: 226875015 clock cycles
14751:              time needed for relocation: 223635459 clock cycles (98.5%)
14751:                   number of relocations: 24432
14751:        number of relocations from cache: 45710
14751:             time needed to load objects: 2969083 clock cycles (1.3%)


...whereas all we seem to get in debian is a simple listing of
relocations. Thanks in advance for any information.
                      Jack
------------------------------------------------------------------------------
Jack W. Howarth, Ph.D.                                    231 Albert Sabin Way
NMR Facility Director                              Cincinnati, Ohio 45267-0524
Dept. of Molecular Genetics                              phone: (513) 558-4420
Univ. of Cincinnati College of Medicine                    fax: (513) 558-8474