Prelinking apps

[Scott James Remnant]

On Tue, 2004-10-05 at 14:26 -0400, Dmitriy Kropivnitskiy wrote:

> From my observations after prelinking my system became somewhat more
> responsive, but barely noticeably so. Personal results may vary.
> 
Have you actually performed any real benchmarks on this?

Ensure you've got libc6-i686 installed, and you can find out how much
time is being spent on relocations using:

descent scott% LD_DEBUG=statistics /lib/tls/i686/cmov/ld-linux.so.2 /usr/bin/gedit
     19055:
     19055:     runtime linker statistics:
     19055:       total startup time in dynamic loader: 95427223 clock cycles
     19055:                 time needed for relocation: 87261064 clock cycles (91.4%)
     19055:                      number of relocations: 2720
     19055:           number of relocations from cache: 2599
     19055:                time needed to load objects: 7556171 clock cycles (7.9%)
     19055:
     19055:     runtime linker statistics:
     19055:                final number of relocations: 9238
     19055:     final number of relocations from cache: 3511

Or whatever app you choose to pick on; be sure to do this a few times to
get everything in the page cache and then average the last 5 results.

Compare a fresh Ubuntu system with a prelinked one.

descent scott% LD_DEBUG=statistics /lib/tls/i686/cmov/ld-linux.so.2 /usr/bin/gedit
     19314:
     19314:     runtime linker statistics:
     19314:       total startup time in dynamic loader: 90071299 clock cycles
     19314:                 time needed for relocation: 82785218 clock cycles (91.9%)
     19314:                      number of relocations: 2720
     19314:           number of relocations from cache: 2599
     19314:                time needed to load objects: 6686188 clock cycles (7.4%)
     19314:
     19314:     runtime linker statistics:
     19314:                final number of relocations: 9279
     19314:     final number of relocations from cache: 3511

Scott
-- 
Scott James Remnant
scott at canonical.com
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