URGENT : elf_update - low performance with large files ? (fwd)

Anitha Boyapati anithab@sankhya.com
Wed Jul 25 10:27:00 GMT 2007


 Firstly, I would say my message is somewhere completely off the topic on 
either of the lists. But I dont know where to ask for help. I searched and
searched for all pointers on libelf.

 Now, I use an age-old version probably - libelf.so.0.8.2.
I donno from where I got it, but probably from mr511 site only.

 So this libelf, I use, in reading and writing elf object files.
While library appears doing the work smartly for smaller files (elf object 
files), it sucks at rather too large files ( ~ 100,000). Profiling shows 
98% of the time is spent only in elf_update(). ( took nearly 2 hours for 
creating objectfile of an 500,000 lined assembly file )

 Does anyone have any idea where should I find some tips for avoiding this 
? Is it something really to do with libelf only ? Any pointers are really 
helpful. This kinda ASAP for me.

 Incase required, please mail me removing cc list so as not to spam every 
 one (Please see the message below for further details).


Anitha B
@S A N K H Y A

---------- Forwarded message ----------
Date: Wed, 25 Jul 2007 15:15:24 +0530 (IST)
From: Anitha Boyapati <anithab@linux42.sankhya.com>
To: libelf@mr511.de
Subject: URGENT : elf_update - low performance with large files ?

 I am a user of libelf. I am using libelf to create and update elf object 
files by an assembler. Now the biggest problem is - elf_update.

 For an assembly file of about 500000 lines, the performance is unusually 
low. Profiling shows 98% of the timespent in elf_update !

 I use a memory image update (ELF_C_NULL) so as to defer writing to actual 
file until much later. What I would like to know is :

  * elf_update() depends on memory size of the object file being written ?

  * are there any leaks at that point in libelf ?
  * Where can I get performance aspects of libelf - like it slows
    down if for a large memory image of an object file

  Btwn, I am also rather much suprised for not finding anything related
  to libelf other than documenatation ( some mailing list-open..I 
  expected). Maybe I shouldnot have expected something like GCC.

  Sorry if I have sounded rude. Nice to have a tool, but having used it I 
am struck at some unknown place which left me with nothing much to 
contemplate - an awkward situation :(
 Any help appreciated deeply. Thanks

Anitha B
@S A N K H Y A

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