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Re: benchmarking combreloc


Jack Howarth <howarth@nitro.msbb.uc.edu> writes:

> Hello,
>     Has anyone actually benchmarked the effect of combreloc on
> loading programs built with a -z combreloc enabled binutils and
> a glibc built against that as well. I have done some simple benchmarks
> on Debian sid ppc comparing the effects of Jakub's prelinker with
> that obtained with and without combreloc. This was done by using
> the -Wl,-znocombreloc linker flag when linking the t1 tutorial to
> attempt to disable combreloc in a program. 
>
> Below are the observations...

[...]
>
> bogus:/home/howarth/tutorial/t1# LD_DEBUG=statistics ./t1.nocombreloc.unprelinked
> 14345:
> 14345:  runtime linker statistics:
> 14345:    total startup time in dynamic loader: 1955297 clock cycles
> 14345:              time needed for relocation: 1882018 clock cycles (96.2%)
> 14345:                   number of relocations: 9647
> 14345:        number of relocations from cache: 22744

Try it for larger programs.  Most relocations are from the cache - and
using that gave is a major improvement.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj


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