benchmarking combreloc
Andreas Jaeger
aj@suse.de
Wed Oct 31 00:26:00 GMT 2001
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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