[RFC] makedumpfile, crash: LZO compression support

[Atsushi Kumagai]

Hello Hatayama-san,

> How about the patch adding compression/IO time report?
> I intended it only for the presentation of this RFC.

I think the above patch was posted only for this discussion,
and I won't merge it into the makedumpfile.


> I'll post the corresponding patch in crash's side after crash 6.0.2 is
> released, waiting for new configuration editing feature as Dave has
> explained.

If the Crash supports LZO compression, I'll merge the feature into 
the makedumpfile.


Thanks.
KUMAGAI, Atsushi


On Wed, 07 Dec 2011 10:03:42 +0900 (   )
HATAYAMA Daisuke <d.hatayama at jp.fujitsu.com> wrote:

> Hello Kumagai-san,
> 
> Thanks for the evaluation.
> 
> So I'll re-post the patch soon removing RFC prefix in header. But
> there is a remaining fix for checking command-line parameters relevant
> to addition of the 'l' option.
> 
> How about the patch adding compression/IO time report?
> I intended it only for the presentation of this RFC.
> 
> I'll post the corresponding patch in crash's side after crash 6.0.2 is
> released, waiting for new configuration editing feature as Dave has
> explained.
> 
> Thanks.
> HATAYAMA, Daisuke
> 
> From: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
> Subject: Re: [RFC] makedumpfile, crash: LZO compression support
> Date: Mon, 5 Dec 2011 17:50:55 +0900
> 
> >> > 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?
> > 
> > 
> > Thanks.
> > KUMAGAI, Atsushi
> > 
> >> 
> >> That's very helpful. Thanks in advance.
> >> 
> >> But of course I'm also still looking for alternative way.
> >> 
> >> Thanks.
> >> HATAYAMA, Daisuke
> >>