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

[Mark Hatle <mark.hatle@windriver.com>]

On 10/26/15 2:56 PM, Martin Jansa wrote:
> 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.

If I get things working again, I'll look into that.  I suspect that was fixed
shortly after, I remebmer there being some debug/dwarf patches going in around
that time frame.

--Mark

> 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
>>>>
>>>> -- 
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>>>
>>
>