Deltarpm xz problem with PPC generated rpms?

[Ben Boeckel]

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Dave Airlie wrote:

> On Sun, 2009-09-13 at 19:43 +0300, Jonathan Dieter wrote:
>> Deltarpm seems to be unable to generate correct rpms for 
deltarpms
>> generated from noarch rpms.  The uncompressed payload is 
correct, but
>> the compressed xz payload is different.
>> 
>> To test, using Rawhide's deltarpm, try running "applydeltarpm 
- -r
>> anjuta-doc-2.27.3.0-3.fc12.noarch.rpm
>> anjuta-doc-2.27.3.0-3.fc12_2.27.92.0-1.fc12.noarch.drpm 
test.rpm".  You
>> should end up with an md5 mismatch.  If you rpm2cpio 
test.rpm, you'll
>> find that the uncompressed cpio archive is identical to that 
of
>> anjuta-doc-2.27.92.0-1.fc12.noarch.rpm.
>> 
>> As I understand it, noarch rpms are generated on PPC 
builders.
>> 
>> I suspect this problem is because of one of two reasons:
>> 1. The version of xz on the PPC builders is a different 
version than
>> that on the other builders?
>> 2. xz generates different compressed files when run on 
different
>> architectures
>> 
>> If it is #2, this is a major problem (at least for yum-
presto) because
>> the whole purpose of deltarpm is to regenerate the original 
(compressed)
>> rpm, given an older version and a deltarpm.  If we can't do 
that, the
>> regenerated package won't pass the signature check and will 
be
>> re-downloaded in full.
>> 
>> I have access to i586 and x86_64 systems, but no PPC systems.  
Could
>> someone either give me access to a PPC system or verify 
themselves
>> whether xz generates different files on different 
architectures (all
>> other things being equal).
> 
> It doesn't.
> [airlied at pegasus ~]$ md5sum lm93_busted.o 
> d7174fc439c4678927725d06de4f18a2  lm93_busted.o
> [airlied at pegasus ~]$ xz -z -c lm93_busted.o | md5sum
> 86dbb83fea5f4e2f77396b3f491a0cc1  -
> 
> [airlied at ppcg5 ~]$ md5sum lm93_busted.o
> d7174fc439c4678927725d06de4f18a2  lm93_busted.o
> [airlied at ppcg5 ~]$ xz -z -c lm93_busted.o | md5sum
> acf84a6c173b040f6cf8ea96c7daa513  -
> 
> 
> thats just a random file I had on my machine here,
> first is x86 32-bit, second is ppc.
> xz-4.999.9-0.1.beta.fc12 on both.
> 
> Dave.
> 
>> 
>> Jonathan
>> -- 
>> fedora-devel-list mailing list
>> fedora-devel-list at redhat.com
>> https://www.redhat.com/mailman/listinfo/fedora-devel-list
> 

When I was playing around with xz after it came out, it detects 
the processor and memory available to it and defaults to a 
different compression quality based on that. Maybe if the 
compression quality and memory usage is set in the command line, 
you'd get the same output.

boeckb at bronto-burt % md5sum eeepc.pdf
efbb35dcb6903fa4a8be91a717ae5c97  eeepc.pdf
boeckb at bronto-burt % xz -c -f eeepc.pdf | md5sum
b7d67d9b8b6a3ac00d9fcfab67ebd93b  -
boeckb at bronto-burt % xz -c -f -5 eeepc.pdf | md5sum
56a269074d015f6d46051a5ecf8d32da  -

[data at cledwyn ~]$ xz -c -f eeepc.pdf | md5sum
5120f453bf577d58e3e94786e7bc5df1  -
[data at cledwyn ~]$ xz -c -f -5 eeepc.pdf | md5sum
56a269074d015f6d46051a5ecf8d32da  -

bronto-burt 3.0GHz x86_64 4GB   RAM
cledwyn     667MHz i686   192MB RAM

xz-4.999.8-0.8.beta.20090817git.fc11 for both

- --Ben
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