Re: [jethro/master][PATCH 1/1] local.conf.sample: Disable image-prelink by default

[Martin Jansa <martin.jansa@gmail.com>]

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On Mon, Oct 26, 2015 at 02:18:12PM -0500, Mark Hatle wrote:
> On 10/26/15 1:15 PM, Martin Jansa wrote:
> > On Mon, Oct 26, 2015 at 10:30:54AM -0500, Mark Hatle wrote:
> >> Due to problems with the prelinker itself, we need to disable the
> >> image-prelink by default.  This will hopefully be re-enabled in the near
> >> future.
> > 
> > Acked-by: Martin Jansa <Martin.Jansa@gmail.com>
> > 
> > We had to disable it in our builds back in Dylan days.
> 
> FYI this is working just fine in Dizzy.  I've heard reports it works in Fido.
> This is the first that I know it's universally broken.  (It's possible there
> were some issues in Fido, as I have not verified it either way.. but Dizzy
> definitely works and passes expected testings.)

The main reason why we disabled it back then was that it was causing
debug symbols in -dbg packages not matching the prelinked binary in the
image

  The size of dynamic relocation section(rel.dyn) was changed from 0027a0
  to 003b70 by prelinking. Hence, the code section offset was also changed
  from 015550 to 016920.
  So, we can not use the dwarf file (.debug/libc-2.14.1.so) made before
  prelinking.

  The number of relocations was 1296 when i use prelinked libraries.
  This value was same on non-prelink. But the number of relative
  relocations has decreased from 2296 to 328.

Then we did some benchmarks on our target and they didn't show any
significant difference with and without prelink, for 4 stages of our
boot we got:

7.06 -> 7.08, 0.28%
5.63 -> 5.75, 2.09%
10.47 -> 10.53, 0.53%
26.11 -> 26.15, 0.15%

So we have disabled it and never looked back.

Regards,

> >> Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
> >> ---
> >>  meta/conf/local.conf.sample | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample
> >> index 3ae24ab..9d1480e 100644
> >> --- a/meta/conf/local.conf.sample
> >> +++ b/meta/conf/local.conf.sample
> >> @@ -128,7 +128,9 @@ EXTRA_IMAGE_FEATURES = "debug-tweaks"
> >>  #   - 'image-swab' to perform host system intrusion detection
> >>  # NOTE: if listing mklibs & prelink both, then make sure mklibs is before prelink
> >>  # NOTE: mklibs also needs to be explicitly enabled for a given image, see local.conf.extended
> >> -USER_CLASSES ?= "buildstats image-mklibs image-prelink"
> >> +# NOTE: image-prelink is currently broken due to problems with the prelinker.  It is advised
> >> +# that you do NOT run the prelinker at this time. 
> >> +USER_CLASSES ?= "buildstats image-mklibs"
> >>  
> >>  
> >>  #
> >> -- 
> >> 1.9.3
> >>
> >> -- 
> >> _______________________________________________
> >> Openembedded-core mailing list
> >> Openembedded-core@lists.openembedded.org
> >> http://lists.openembedded.org/mailman/listinfo/openembedded-core
> > 
> 

-- 
Martin 'JaMa' Jansa     jabber: Martin.Jansa@gmail.com

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