[Crash-utility] [RFC] makedumpfile, crash: LZO compression support

[Dave Anderson]

----- Original Message -----
> > > Hello Hatayama-san,
> > > 
> > > Thank you for your work.
> > > 
> > >> Performance Comparison:
> > >> 
> > >>   Sample Data
> > >> 
> > >>     Ideally, I must have measured the performance for many enough
> > >>     vmcores generated from machines that was actually running, but now
> > >>     I don't have enough sample vmcores, I couldn't do so. So this
> > >>     comparison doesn't answer question on I/O time improvement.  This
> > >>     is TODO for now.
> > > 
> > > I'll measure the performance for actual vmcores by makedumpfile.
> > > Please wait for a while.
> 
> I measured the performance of makedumpfile for some vmcores.
> Please see below.
> 
> 
> Sample Data
>   
>   To simulate a working server, I captured VMCOREs while almost all pages
>   were alloceted and filled with random data. (See attached file "fill_random.c")
> 
>   I captured the VMCOREs of 5GB, 7.5GB and 10GB in the same condition.
> 
> How to measure
> 
>   I measured the total execution time and the size of output file.
> 
>   $ time makedumpfile --message-level 16 [-c|-l| ] vmcore dumpfile
> 
> Result
> 
>     See attached file "result.txt".
> 
> 
> This time, lzo's compression was the quickest, and lzo's compression ratio is
> almost the same(only a bit worse) as zlib's.
> It seems good, and I will merge the patch set into the makedumpfile.
> 
> What is your opinion, Dave?

Well, I'm not particularly thrilled about the requirement of three additional
packages and the extra library.  In the most recent crash release I did add
the capability of easily adding extra libraries to the build procedure.  But
if the feature ever becomes the default in a future RHEL distribution, then I
guess I won't have any choice but to force the requirement of the packages and
library.

Dave
 
 
> Thanks.
> KUMAGAI, Atsushi
> 
> > 
> > That's very helpful. Thanks in advance.
> > 
> > But of course I'm also still looking for alternative way.
> > 
> > Thanks.
> > HATAYAMA, Daisuke
> > 
> 
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